Windows Explorer freezes on right-click

Running Windows 7 Home

Windows explorer is now freezing when I right-click files -- get "not responding" and have
to restart explorer -- which does not clear the problem up.

Also apps are freezing opening and/or saving files -- notepad, MS Office 2013, Nero 2014 and others.

Thanks,

Have run sfc scannow and now verifyonly.
I got the following from verifyonly

2014-12-21 19:34:59, Info CSI 0000005e [SR] Beginning Verify and Repair transaction
2014-12-21 19:35:01, Info CSI 00000060 [SR] Cannot repair member file [l:18{9}]"Query.dll" of Microsoft-Windows-Content-Indexing-Common, Version = 6.1.7601.17730, 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
2014-12-21 19:35:02, Info CSI 00000063 [SR] Cannot repair member file [l:18{9}]"Query.dll" of Microsoft-Windows-Content-Indexing-Common, Version = 6.1.7601.17730, 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
2014-12-21 19:35:02, Info CSI 00000064 [SR] This component was referenced by [l:154{77}]"Package_1_for_KB2645610~31bf3856ad364e35~amd64~~6.1.2.0.2645610-2_neutral_GDR"
2014-12-21 19:35:02, Info CSI 00000067 [SR] Could not reproject corrupted file [ml:520{260},l:46{23}]"\??\C:\Windows\System32"\[l:18{9}]"Query.dll"; source file in store is also corrupted
2014-12-21 19:35:02, Info CSI 00000069 [SR] Verify complete

It appears this file query.dll is corrupt -- is this a Windows file??
Do you think this is the cause of this explorer trouble?

Thanks