Well here is the whole story. HP Dv2050us laptop. It was running very slow and had conflicts with Bitdefender 10 installed and also Spydoctor (don't remember the version). after few impossible days of running very slow, it turn off and when I tried to restart it continue restarting without even reaching the welcome screen. I figured out that I was getting continues Blue Screen Of Death, BSOD, and tried to restart in safe or any single mode, without success. Entered into the setup and tried to do recovery mode, no success, my computer was not "detecting" any Hard drive. I tried with the same hd in a desktop (with an enclosure) and didn't work, but I could read it with a recovery software, so files are recovered now. Installed new HD in laptop, did all the hard work of loading SATA driver with a floppy disk and was able to install XP. Everything worked perfect. SURPRISE, installing Bitdefender 10 and SpyDoctor, it crashed again, It doesn't see any HD. Please, do you know whats going on?