Not sure what this is, But I have gotten this a few times even after a recent Windows 7 x64 install
Some malware camouflage themselves as SearchProtocolHost.exe, particularly if they are located in c:\windows or c:\windows\system32 folder. Thus check the SearchProtocolHost.exe process on your pc whether it is pest.
Try to start up in Safe Mode and then perform a full av scan, then report back with the results,
also look here for these kind of problems: http://blogs.technet.com/b/joscon/archive/2011/02/17/windows-7-2008-r2-service-pack-1-fails-with-0x800f0a12.aspx
polonus
I used to (haven’t recently) get alerts on searchprotocol…when saving html source code from malicious sites (to upload to VT)…AFAIK windows tried to index it to make searching quicker, causing an alert…