text: my computer at home says no operating system found...? i bought xp and tried to install it, now it won't let me install, it just says   no hard disk drives found. i opened the computer and can hear the hard drive running so i know it has power.  any ideas? sounds like a communication error between the bios and the harddrive, or you have a bad harddrive.  be sure to check the following things....  1.  make sure the harddrive is set up correctly in the computer.  meaning that the proper cables are plugged into the correct slots on the motherboard and the harddrive is set on master.  2.  make sure the harddrive is set up in the bios to be read by the system during the boot up sequence.  this is how the system knows that a harddrive is on the system.  3.  see if you can boot up the pc normally without trying to install windows.  if this does work then there's a problem with the windows installation cd or the way you're trying to install windows xp.  if none of the solutions above seem to work, then most likely you have a bad harddrive.