Update on this:
Checked device manager again, and viewed hidden devices: gave an error for the device "User Mode Driver Frameworks Platform Driver" - This device is not present, is not working properly, or does not have all its drivers installed. (Code 24)
Following google advice, I checked the services in Computer Management: the service I was directed to look for (Windows Driver Foundation - User-mode Driver Framework) was not started, and right clicking and selecting Start gave the following error message - Error 1068 The dependency service or group failed to start
Good old google led me to check whether WudfPf.sys file exists in the %WinDir%\system32\drivers folder - it doesn't so I'm guessing that's what the issue is but I'm not comfortable downloading alleged repairs or installs from the internet and Microsoft doesn't appear to offer any support on this (that I could find).
I have now run (as suggested by ThrashZone - thank you!) sfc /scannow and it identified but could not repair the problem. I get the following text part way through the verification process:
2015-03-31 13:31:22, Info CSI 000000a8 [SR] Verifying 100 (0x0000000000000064) components
2015-03-31 13:31:22, Info CSI 000000a9 [SR] Beginning Verify and Repair transaction
2015-03-31 13:31:27, Info CSI 000000ac [SR] Cannot verify component files for Microsoft-Windows-DriverFrameworks-UserMode.Resources, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture = [l:10{5}]"en-US", VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral, manifest is damaged (TRUE)
2015-03-31 13:31:32, Info CSI 000000ae [SR] Cannot repair member file [l:20{10}]"WUDFPf.sys" of Microsoft-Windows-DriverFrameworks-UserMode, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2015-03-31 13:31:32, Info CSI 000000b0 [SR] Cannot repair member file [l:80{40}]"MsftWdf_User_01_11_00_Inbox_Critical.Wdf" of Microsoft-Windows-DriverFrameworks-UserMode, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2015-03-31 13:31:36, Info CSI 000000b2 [SR] Cannot repair member file [l:20{10}]"WUDFPf.sys" of Microsoft-Windows-DriverFrameworks-UserMode, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2015-03-31 13:31:36, Info CSI 000000b3 [SR] This component was referenced by [l:156{78}]"Package_1_for_KB2685813~31bf3856ad364e35~amd64~~6.1.1.11.2685813-2_neutral_GDR"
2015-03-31 13:31:36, Info CSI 000000b5 [SR] Cannot repair member file [l:80{40}]"MsftWdf_User_01_11_00_Inbox_Critical.Wdf" of Microsoft-Windows-DriverFrameworks-UserMode, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2015-03-31 13:31:36, Info CSI 000000b6 [SR] This component was referenced by [l:156{78}]"Package_1_for_KB2685813~31bf3856ad364e35~amd64~~6.1.1.11.2685813-2_neutral_GDR"
2015-03-31 13:31:36, Info CSI 000000b9 [SR] Could not reproject corrupted file [ml:520{260},l:62{31}]"\??\C:\Windows\System32\drivers"\[l:20{10}]"WUDFPf.sys"; source file in store is also corrupted
2015-03-31 13:31:36, Info CSI 000000bc [SR] Could not reproject corrupted file [ml:520{260},l:62{31}]"\??\C:\Windows\System32\drivers"\[l:80{40}]"MsftWdf_User_01_11_00_Inbox_Critical.Wdf"; source file in store is also corrupted
2015-03-31 13:31:36, Info CSI 000000bf [SR] Recovered manifest from backup for Microsoft-Windows-DriverFrameworks-UserMode.Resources, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture = [l:10{5}]"en-US", VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral
2015-03-31 13:31:37, Info CSI 000000c4 [SR] Verify complete
And the following text and the end, during the repair process:
2015-03-31 13:59:38, Info CSI 00000349 [SR] Repairing 2 components
2015-03-31 13:59:38, Info CSI 0000034a [SR] Beginning Verify and Repair transaction
2015-03-31 13:59:38, Info CSI 0000034c [SR] Cannot repair member file [l:20{10}]"WUDFPf.sys" of Microsoft-Windows-DriverFrameworks-UserMode, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2015-03-31 13:59:38, Info CSI 0000034e [SR] Cannot repair member file [l:80{40}]"MsftWdf_User_01_11_00_Inbox_Critical.Wdf" of Microsoft-Windows-DriverFrameworks-UserMode, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2015-03-31 13:59:38, Info CSI 00000351 [SR] Cannot verify component files for Microsoft-Windows-DriverFrameworks-UserMode.Resources, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture = [l:10{5}]"en-US", VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral, manifest is damaged (TRUE)
2015-03-31 13:59:39, Info CSI 00000354 [SR] Recovered manifest from backup for Microsoft-Windows-DriverFrameworks-UserMode.Resources, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture = [l:10{5}]"en-US", VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral
2015-03-31 13:59:39, Info CSI 00000356 [SR] Cannot repair member file [l:20{10}]"WUDFPf.sys" of Microsoft-Windows-DriverFrameworks-UserMode, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2015-03-31 13:59:39, Info CSI 00000357 [SR] This component was referenced by [l:156{78}]"Package_1_for_KB2685813~31bf3856ad364e35~amd64~~6.1.1.11.2685813-2_neutral_GDR"
2015-03-31 13:59:39, Info CSI 00000359 [SR] Cannot repair member file [l:80{40}]"MsftWdf_User_01_11_00_Inbox_Critical.Wdf" of Microsoft-Windows-DriverFrameworks-UserMode, Version = 6.1.7601.17803, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2015-03-31 13:59:39, Info CSI 0000035a [SR] This component was referenced by [l:156{78}]"Package_1_for_KB2685813~31bf3856ad364e35~amd64~~6.1.1.11.2685813-2_neutral_GDR"
2015-03-31 13:59:39, Info CSI 0000035d [SR] Could not reproject corrupted file [ml:520{260},l:62{31}]"\??\C:\Windows\System32\drivers"\[l:20{10}]"WUDFPf.sys"; source file in store is also corrupted
2015-03-31 13:59:39, Info CSI 00000360 [SR] Could not reproject corrupted file [ml:520{260},l:62{31}]"\??\C:\Windows\System32\drivers"\[l:80{40}]"MsftWdf_User_01_11_00_Inbox_Critical.Wdf"; source file in store is also corrupted
2015-03-31 13:59:39, Info CSI 00000362 [SR] Repair complete
2015-03-31 13:59:47, Info CSI 00000367 [SR] Committing transaction
2015-03-31 13:59:48, Info CSI 0000036b [SR] Verify and Repair Transaction completed. All files and registry keys listed in this transaction have been successfully repaired
The sfc scan gave me the following message on completion:
Windows Resource Protection found corrupt files but was unable to fix some of them
So ... now what? lol. There is no windows disk (pre-installed) and no backup was taken on first launch (daughter's laptop, since when do kids listen to parents?), and the above says that the backup version sfc repairs from was also corrupt.
Microsoft says "manually replace the corrupted file with a known good copy of the file." - can this be from any Windows PC, or any Windows 7 PC, regardless of version? Or does it have to be another Windows 7 Home Premium SP1 system that I get the good files from? Or is there somewhere safe I can download them from? And do I just replace the corrupt ones with copy and paste, or is there a process I'll need to go through to get the good files working correctly?