I've had my Dell XPS 400 for about a year now and I haven't encountered many problems with it. I logged on as usual this morning, then logged off a while later. My sister then got on, and after she got off I went to get on again. She had shut the computer down, so I turned it on. It booted up normally until we got to the Windows XP loading screen. It usually only spends a second on that screen, but this time it just kept loading and loading and loading. Finally after about five minutes a blue screen came up telling me to either restart my computer, or if the problem persists to uninstall any software and hardware I've installed recently. My most recent software download was a week ago (the computer worked fine after it until now) and my most recent hardware addition was a month ago. Anyways, I thought it may have been a virus so logged in in Safe Mode and initiated McAfee Virus Scan. It started scanning, then just froze at "9 files scanned". I repeated this a couple of times, to no avail. Occasionally the computer would even freeze, then take me directly to the blue screen I mentioned before. Also, I cannot access the internet (I am posting this from a friends computer)

My question: what exactly is happening, and how do I fix it? I can provide more information as well. Thank you for any information reguarding my problem.