BleepingComputer.com: Help! I can't log in!

So last night, I was browsing the internet...when my Sandboxie alerted me I hadn't erased the Sandbox in 9 days, and I should do so. This reminded me, I hadn't cleaned out my temp files in months. I regularly use the program TFC, as after a while all my temp files slow down the computer. Typically, there is no problem, and the computer is good as new. Actually, there is only one previous time I can think of that I had a problem with TFC, and that is the time that after using it, I couldn't get past the boot screen, so I pressed the button to run system diagnostics, and after it passed all the tests, let it reboot. All was well.

However, this time, I got all the way to the login screen and even typed in my password. After clicking "ok" however, I got a message which said "The User Logon service could not be reached" or something along those lines. I figured, "Hey, well, I'll try it again tomorrow." So I shut it down, and turned it on again this morning. Still wouldn't work.

About this time I got a little nervous, so I decided to try booting into safe mode. This worked (to my relief) and I was able to log in, but...it loaded a default profile, claiming it couldn't properly log me in. For good measure, I checked to see if my files were still there (which they were) and rebooted to look at the system repair tools. First I tried the "Fix Problems with Boot-up" and it found no problems. Then I decided to try and use a restore point, but the System Restore window never loaded!

I finally decided to try Safe Mode with Networking, which again loaded into the default profile, and I'm accessing Bleeping Computer from it now.

I run Windows Vista SP2. Any help would be greatly appreciated!