Ok so here is what happened.I know this post is old and I am re posting this.Anyway I wanted to install Windows XP (I know the os is old) over my Windows Vista HP Pavilion DV4 1120US.So I added the sata drivers to the XP cd and successfully load the XP disc at startup.The first time I tried to install it started checking my computers hard drive and when it rebooted it said "error loading the operating system."So I tried on more time and I formatted the partition I made for XP.Then it started installing Windows XP onto that partition.Then after that was done my computer rebooted and then it was stuck at the HP logo.Luckly I have a Toshiba laptop as a backup.So I tried to figure out how to fix that.When I turn on the computer it gets stuck on the HP logo.On the bottom left corner it say "press the esc key for startup menu."I tried doing that but I can't do anything.Then I took the hard drive out and I was able to go into the stratup menu.The only thing I could do right now is successfully boot the computer up by using a linux cd but only if I take the hard drive out or else I can't do anything.So I am guessing something is fishy with the hard drive because when I take it I am able to access the startup menu unless if I don't take it out.What is my probelm? Help please? Is my hard drive dead? Do I need to replace it? I think I need to replace it and recover the os.