IE10 will not updated after downgrading to IE8

You had a fair amount of corruption present -
from your first SFC scan this morning...

Code:

 Line 13950: 2014-05-15 10:47:11, Info                  CSI    000003d8 [SR] Repairing 47 (0x000000000000002f) components
 Line 13951: 2014-05-15 10:47:11, Info                  CSI    000003d9 [SR] Beginning Verify and Repair transaction

(all errors found were fixed)

From your CheckSUR log...

Code:

Checking Component Store
(f) CSI Catalog Corrupt 0x80096004 winsxs\Catalogs\000a64cf10d76850f858deeaf46aea7438659688e66a7defe0c8e4a3b63c3d40.cat wave.wcr10.cryptoruntime_1aaab1af848ab112_1.0.2.12_b0998081cbbe8b7e 
(fix) CSI Catalog Corrupt CSI File Replaced Deleted CatalogThumbprint
(f) CSI Catalog Corrupt 0x80096004 winsxs\Catalogs\98bd7d2325d7c1e423b309b75ed2620c72b78636a78b3e5b4dce0f655cee4020.cat wave.wcr10.cryptoruntime_1aaab1af848ab112_1.0.2.12_68ec49aab7426278 
(fix) CSI Catalog Corrupt CSI File Replaced Deleted CatalogThumbprint
(f) CSI Catalog Corrupt 0x80096004 winsxs\Catalogs\686983517465b20f5a836aef0c88f45ff625e5160525bfa899653a467bb2bebf.cat wave.super.superprotocol_1aaab1af848ab112_2.0.0.8_209ce444415610f4 
(fix) CSI Catalog Corrupt CSI File Replaced Deleted CatalogThumbprint
(f) CSI Catalog Corrupt 0x80096004 winsxs\Catalogs\699f5031547c609dc1fc54f1b25172c4c1aa5e4ca7350f1f56ae348c7db81cf5.cat wave.super.superprotocol_1aaab1af848ab112_2.0.0.8_d8efad6d2cd9e7ee 
(fix) CSI Catalog Corrupt CSI File Replaced Deleted CatalogThumbprint

- again, all errors found were fixed.


There are a couple of errors in the background CBS which may be the source of your problem...

Code:

2014-05-15 12:40:47, Info                  CSI    000000dc Performing 1 operations; 1 are not lock/unlock and follow:
  Stage (1): flags: 8 app: [Microsoft-Windows-InternetExplorer-Deployment, Version = 10.2.9200.16521, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral]) comp: (null) man: @0x35befe8
2014-05-15 12:40:48, Info                  CSI    000000dd Stage component failed, manifest does not match previously staged manifest for identity
2014-05-15 12:40:48, Error                 CSI    000000de@2014/5/15:16:40:48.086 (F) d:\win7sp1_gdr\base\wcp\componentstore\csd_transact.cpp(1370): Error STATUS_SXS_MANIFEST_IDENTITY_SAME_BUT_CONTENTS_DIFFERENT originated in function CCSDirectTransaction::StageComponent expression: (null)
[gle=0x80004005]
2014-05-15 12:40:58, Error                 CSI    000000df (F) STATUS_SXS_MANIFEST_IDENTITY_SAME_BUT_CONTENTS_DIFFERENT #193457# from CCSDirectTransaction::OperateEnding at index 0 of 1 operations, disposition 2[gle=0xd015001c]
2014-05-15 12:40:58, Error                 CSI    000000e0 (F) HRESULT_FROM_WIN32(ERROR_SXS_MANIFEST_IDENTITY_SAME_BUT_CONTENTS_DIFFERENT) #192835# from Windows::ServicingAPI::CCSITransaction::ICSITransaction_PinDeployment(Flags = 0, a = Microsoft-Windows-InternetExplorer-Deployment, Version = 10.2.9200.16521, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral, cb = (null), s = (null), rid = [115]"Microsoft-Windows-InternetExplorer-VistaPlus-Update~31bf3856ad364e35~amd64~~10.2.9200.16521.Internet-Explorer-amd64", rah = (null), manpath = [183]"\\?\C:\Users\JDS\AppData\Local\Temp\5AE33B35-9AB3-4C82-A54B-89E668C2111D\amd64_microsoft-windows-i..explorer-deployment_31bf3856ad364e35_10.2.9200.16521_none_cba0e8fb897ea591.manifest", catpath = [168]"\\?\C:\Users\JDS\AppData\Local\Temp\5AE33B35-9AB3-4C82-A54B-89E668C2111D\Microsoft-Windows-InternetExplorer-VistaPlus-Update~31bf3856ad364e35~amd64~~10.2.9200.16521.cat", ed = 0, disp = 0)[gle=0x80073715]
2014-05-15 12:40:59, Info                  CBS    Failed to pin deployment while resolving Update: Internet-Explorer-amd64 from file: \\?\C:\Users\JDS\AppData\Local\Temp\5AE33B35-9AB3-4C82-A54B-89E668C2111D\amd64_microsoft-windows-i..explorer-deployment_31bf3856ad364e35_10.2.9200.16521_none_cba0e8fb897ea591.manifest [HRESULT = 0x80073715 - ERROR_SXS_MANIFEST_IDENTITY_SAME_BUT_CONTENTS_DIFFERENT]
2014-05-15 12:40:59, Info                  CBS    Failed to resolve item[0] in Package: Microsoft-Windows-InternetExplorer-VistaPlus-Update~31bf3856ad364e35~amd64~~10.2.9200.16521, Update: Internet-Explorer-amd64 [HRESULT = 0x80073715 - ERROR_SXS_MANIFEST_IDENTITY_SAME_BUT_CONTENTS_DIFFERENT]
2014-05-15 12:40:59, Info                  CBS    Failed to resolve execution update. [HRESULT = 0x80073715 - ERROR_SXS_MANIFEST_IDENTITY_SAME_BUT_CONTENTS_DIFFERENT]
2014-05-15 12:40:59, Error                 CBS    Failed to resolve execution package: Microsoft-Windows-InternetExplorer-VistaPlus-Update~31bf3856ad364e35~amd64~~10.2.9200.16521 [HRESULT = 0x80073715 - ERROR_SXS_MANIFEST_IDENTITY_SAME_BUT_CONTENTS_DIFFERENT]

This usually indicates corruption in the registry - but it's the first time I've seen this specific type, so it'll take me a while to work out what's going on.

It may be corruption in the SoftwareDistribution folder - have you tried installing from the standalone installer from here? Download Internet Explorer 11 for Windows 7 64-bit Edition and Windows Server 2008 R2 64-bit Edition from Official Microsoft Download Center

I'd rather check some of the other stuff first - but yes, it would rebuild itself.


I need to have a look at your COMPONENTS registry hive

Please copy the C:\Windows\System32\config\COMPONENTS file (no extension) to your desktop and then compress it - upload the compressed file to your favoured fileshare site (preferably Dropbox or OneDrive) and post a link.

Boot to Safe Mode and try from there - the system is obviously attempting to load it in normal mode and failing.

The file is rather smaller than we normally see - about 30MB rather than 40MB+

This makes me think that there's a good chance that a repair install is going to be necessary

I'll go into more detail when I've had time to have a good look through it.

There appear to be large numbers of entries missing from the registry, at least in the IE10 area I looked at.
This could indicate a number of things - from being perfectly normal (given the machine's history), through to being a sign of major corruption.

Have you been using any form of registry cleaner/optimizer/defragger? If so, does it have an 'undo' option?