By replacing your hard drive you have removed your operating system (the software that drives the computer). The fix is to put the old drive back.
If the old drive was slow it doesn't mean it was broken it means it was fragmented. When you have put the old drive back, use the System Tools Defragmenter to defrag the drive. You can use your new drive as the 'second' drive. Drives usually come with instructions on how to do this.
Recovery CDs have to be from AT LEAST the same make and model of PC. A lot of current ones are actually keyed to the Microsoft label on the bottom of the PC.
BTW. I have arready answered this question once. Didn't you like the answer?
Terry, May 2006