i had two computers and the older one took a dump. so i decide to take the hard drive out of one and put it in the other, however my computer didn't have an extra slot so i purchased an IDE cable that had the extra room for the slave drive. i decided to check to see if the hard drive is why the other computer took a dump, so i hooked the old hard drive direcly up and it booted perfectly. When i hooked them both up together the computer will turn on but not boot and i cannot get to the setup screen. I was thinking that i might need to upgrade something, but im not sure and im not sure if my computer can handle the second hard drive. the computer is a compaq deskpro en, but i dont know the model number and im having a hard time locating it. i got the computer from a friend and i dont see it anywhere on, inside, or any of the settings page. so does anyone know if i need an update? thanks for your response

See if this helps the ID:

How Do I Find My Model Number?

If the original cable was a single port cable there is a good chance the motherboard port is a single channel.

If the CD (secondary) cable is dual try that port.