Windows 7 - Add new SATA drive, laptop becomes slow and hangs alot?

I removed an 80GB hard drive from my Lenovo T61 4GB Ram, 1.8ghz Dula Core, Windows 7 Home Premium and replaced with a brand new fujitsu 320gb hard drive.

Ever since doing this my computer has slowed dramatically.

So much so Firefox hangs, Chrome hangs.. even defrag hangs. Basically anything that requires a little bit of system resources will hang.

I don't know if it's because it's a faulty hard drive but I'm beginning to think it is.

What do you guys think?

Cheers

The first thing to try is to remove the drive and then be sure to blow out all of the connectors, in the drive and the laptop, with a can of compressed air. Then reinstall it and see if it makes any difference.
The connectors are very close together and just a tiny hair or dust-bunny can cause enough of an electrical short to cause you problems.

You also want to burn yourself a boot CD with Hitachi Drive Fitness Test and test the drive. The Drive Fitness Test works well for Fujitsu drives.