oh ok, if it's your regular PC, it might be something which is easier to fix. Though it is still probably a driver
problem. So please, go to the manufacturer website of every part in your computer (motherboard, graphics card, sound card, network card, raid controller, etc) and get their drivers
. install them.
First though, open up your computer.
With installing this new hard drive, you may have knocked loose a few connections in your computer. Yes, it might really be that simple.
Start with your hard drive. If it is sata, take out the power cable and the red data cable, and put them back in, and make sure you press them in firmly. Do the same with the red data cable on your motherboard (and any other red data cables on your motherboard.)
Then, take out any expansion cards on your motherboard such as graphics cards, soundcards, etc, and put them back in. For anything but the graphics card, it would be good to see if it's possible to see if they can go in a different slot.
if you see any other cables connected anywhere, press them down to make sure they are well connected.
Also, you put in a new HD. Was windows on the old HD? and did you leave the old HD in there? if so, try to disable the HD and try the computer then (disable the old HD I mean). Now.... don't do all of this at once, first try what I said above, if that doesn't help, try the hard drive thing.
If neither of these things work (drivers, hardware, hard drive) then you are going to have to look for the IRQ conflict.... and that is a tough thing to do.