Since yesterday, I have been having some serious problems with my Compaq Presario 2100 laptop (AMD Athlon XP version). Whenever I used this laptop it would run fine for about thirty minutes, then it would display the Blue Screen of Death with a message mentioning the atapi.sys driver. At first, I thought it was a virus but the virus scanners I have did not come up with any viruses. I ran sfc/scannow to see if there were any corrupted files in the system, but it turned up with no response of any problems. Then, I uninstalled a virtual CD driver program called Daemon Tools as a suggestion from a friend of mine. This temporarily solved the problem, but when I turned on my laptop today, it could not load into Windows (Windows XP Home Edition SP2). Instead, it now shows the usual loading screen, then it displays the Blue Screen of Death with a new message which I can not read because it quickly flashes off to reboot the laptop again. I do not know what is causing this and I am afraid to reformat my hard drive because I have some important documents on my laptop. If anyone could help me, it would be much appreciated.