Make sure that the fans are all running, especially the one on your processor. You may have pulled a wire loose when replacing the HD.
While you have the computer open, clean all the dust from inside it with a can of compressed air. (Do not blow it directly on the fans without stopping them from spinning first. Use a pencil or something non-conductive to stop the fans when you blow the air on them. Overspinning them can damage them)
Make sure all connections are tight.
Even though you set the jumper the same way as it was on the old hard drive, look for the diagram on the new hard drive and make sure the jumper is set correctly. If you only have one hard drive it should be set to master or master with no slave - whatever is applicable.
You didn't remove and replace the processor did you? If you did, you would have needed to clean it and the heat sink and reapply the thermal paste.
Did you format the hard drive first before trying to install Windows?
If you didn't - use the CD that should have come with the hard drive and format it.
By the way, it's a good idea to partition the HD. Use the first partition for the op system and the second for other programs and data.
The software that came with the new hd should give you that capability when you format the hd.
Edited by Enthusiast, 23 March 2006 - 03:25 PM.