PC Start up problems

Well my PC recently had been acting funny, I don't know if this has any signifigance but before I start I might as well say it. Before my PC started acting funny hence the title, I was using Logitech quick cam and it kept freezing everytime I used it so I basically kept having to use the beastly 'end now' and take it down. From there I'd normally use my PC, Now I rebooted and did the same process of using Logitech and it froze so I made it end now BUT I resumed using my pc for the portion of the day and I then told it to shut down from there it just sat at the main desktop for about 10 minutes and still didn't do anything so I had to shut it down using the power button. I used my PC once after that and used it for about a few hours, I then shut it down same thing happened. So I went up stairs for a few hours to play some console gaming and came down later and turned my PC on, It basically starts up normally then says if I want to start in safe mode (There's three safe modes I can start in, I used the first) start using normal settings last used safely and the regular start windows. So my first thought was to just start windows normally, So I proceeded and well... everything went down hill from there. It went to the windows loading screen and then went to a black screen (Usually I see this on most PC's anyways right before it loads the main interface to log in) and instead of going to the interface to log in it restarted the PC over AGAIN, It just goes right back to the menu to select safe modes or start windows and all that stuff. So PLEASE! Someone help me on how to get this working again, And no I don't have any restore disks...

Jam it back in, in the dark.

No restore disks.... Eek.

Well, tell me you tried booting up in safe mode. If you didn't try, please do and report back your results.

If you cant boot to windows in safe mode, grab your XP install disk and come back here.

There's nowhere I can't reach.