Windows XP startup problem?

When I started up my computer this morning it was working just fine, but then I shut it down and as soon as it shutdown I accidentally pressed the power button the second it shut down and now it is not loading Windows XP properly. It brings up the page before the startup with the system recovery and whatnot on it, then it goes to the options that let me choose how I start Windows XP. I have tried all of them and they give the same response where the Windows XP bar starts to load, stops midway, and then flashes a blue screen and starts the whole process all over again. Anyone have an idea as to what is happening and how I can fix it without having to set my computer to factory defaults? This has happened before and I thought it was a virus but apparently not...