What can be wrong with the computer screen?

Computer keeps restarting before log in screen, whats wrong? Can I fix it myself?

• So about 2 or 3 weeks ago, I left my computer alone for about an hour and a half to talk to a friend who came over, when I came back, I had one of those fake computer scan windows show up, my windows task bar was gone showing my background, and my computer was running slower. I closed everything, and tried to log off, but after about 5 mins, it didn't. So, I unplugged it and removed the battery to turn it off. But, after that, every time I turn it on, right before the log on screen, my computer restarts. I've run a test on it to see if my disks are ok and it said everything was fine. Can anybody tell me what exactly is wrong, and if there is a way for me to fix this without taking it to a computer repair shop and without deleting any of my memory (specifically my photos, videos and music)? Any help would really really help alot. I have an HP laptop which is a little over 3 years old and it has Vista. And once again, I can't stress enough how much I don't want to have my photos, videos and music deleted. I haven't started my computer in over a week with the battery removed and unplugged. Thanks in advance!

• Answer:

  A friend had this problem and it was due to malware. He cured it with a free anti-malware program. Google anti-malware on another computer & follow the advice (you have to press F1 I think on startup, & enter Windows Safe Mode). Also google the specific fake computer scan if you can to see what is ont he net - someone else will have got in to their faulty computer & deleted the malware. When you finally get in, DO A BACKUP before anything else including, I suggest, running the anti-malware (if possible) in case it causes a problem - without erasing your last backup. Did you instal something just before the problem? The cause could be something else.