I have Windows 7 64-bit. After turning on my computer this morning, I received an error message: "Interactive logon process initialization has failed. Please consult the event log for more details." I clicked on "OK" and the screen remained black. I then turned off my computer manually and it started in Safe Mode. I was then able to logon. I haven't seen any threads addressing this problem in Windows 7 64-bit, only Windows Vista or Windows 7 32-bit.

The problem might not be related to the architecture, did try anything you've found for win7 32bits? If yes, you should mention it to avoid giving you diagnostics steps you've already tried. If not, and since you can perform safe mode boot, try a clean boot (http://support.microsoft.com/kb/929135) first, that should helps you determine if windows own service and process are a cause to the failure or not. You can also try startup repair (you'll need the OS installation disk or a repair disk created by you): Insert the disk, boot the systems from it Select your language preferences and click next In the System Recovery options dialog click Startup Repair.