Doug, here are some other things to try:

Check out the Windows logs in the event viewer, noting what time it is when you initially log into your account and the freeze starts. If nothing else, it might indicate what's hanging up. From your description, explorer.exe would be my first guess.

You might try running "sfc /scannow" from an elevated command prompt, but report back with the safe mode results first. If everything is normal in safe mode, you may have to go through the tedious process of disabling all non-MS startup items and re-enabling each item one at a time.