Computer boot up problem

Turned on my computer yesterday and it said something on the lines of: We're sorry but windows could not start up properly, this could be caused by a software or hardware change. It gives me the choice of safe mode, safe mode w/networking, safe mode in DOS, restart windows with last known correct settings (or something like that). All the safe mode ones give me a alot oflong DOS commands and then it doesn't start up. The restart windows with last known correct settings takes me to the windows screen with the bar at the bottem like its about to work but then goes to back to boot up menu.The only softwere or hardwere change I can think of is when I tried to play a demo with a 360 controller but I guess I needed a install disk or something so I pulled out and forgot about it. Turned it off late that night, then next morning it would go to the boot up menu.If anyone knows what I can do to fix this PLEASE help. Thanks for any replies in advance.Computer boot up problem
run scan disk and then boot up in safe mode and do a system restore before the problem happened.Computer boot up problem
How do I run scan disk?
Need to get past boot menu to do a system restore. But keeps going back to screen. Any ideas?
What version of windows are you running? Can you use your windows disk, or system restore disks (which ever you have) to repair the windows install?

mask making