Trouble installing new WD10EARS

I thought it would be fairly straightforward to replace a failing a hard drive with a new one–that has not been the case.  My old hard drive (a WD 640GB) gave me a message saying it was going to fail so I bought the new 1TB Caviar Green.  I replaced the hard drive, booted up the computer and the BIOS recognized the new hard drive.  I had problems with the recovery discs from HP (understatement) and had to keep on rebooting my computer.  I had already posted on the HP support forums and followed some of their advice to try and get it to work.  Well,the computer only gets to the HP splash screen and is unresponsive to anything now.  I tried to put back my old hard drive and it does the same thing.  Nothing…works…help

Hi  if you want  HP old HD driver if you have image windows press F11 on boot  for automatic recovery system .