I am using Windows 7 Ultimate RTM also. I have access to Professional through Technet but I am utterly sick of reinstalling Windows.
Now where's that Hackintosh site...?
I really am at a total loss now, this damn issue has crushed me.

Initially I thought it was my Creative X-Fi Xtreme Audio
drivers, as they were causing a similar problem when I used the Sound Control Panel.
I managed to resolve it by removing that particular part of the Creative drivers.
Next up was Microsoft Security Essentials, I'm still not convinced it wasn't something to do with that as this was my only change in software when I installed the RTM build.
I have removed EVERYTHING using ShellExView, and again, it still persists.
Last night I removed my Creative card completely and put it away, that way I can make sure it is definitely NOT anything Creative.
I have ran sfc/scannow which is totally fine, and ran the registry cleaner that is part of CCleaner. Normally I wouldn't use this but I have nothing to lose at this point.
I have checked my startup entries and services and removed any non-essential entries. I have also had a look through the Registry Editor for anything related to 'msvcrt.dll' and 'ntdll.dll', which are ALWAYS the culprits, that might jump out at me.
NOTHING.
I might remove uTorrent and Java as a test but I have never had any problems with either program before.
Lastly, I have also done several thorough scans with Malwarebytes' Anti-Malware, Spybot - Search & Destroy (since removed, MSE (since removed), and avast! Home Edition.
All clean.
Somebody must be able to help!?