Just a word of caution.. not wanting to put you off....

I did this with a seagate drive on my old XP machine and the seagate software didn't work well. After transferring to the new drive I had LOTS of probs with 'file not found' issues and blue screens. In the end I had to reformat the disc and tsart from scratch installing XP etc on the new disc. I might have just been unlucky and this was about 18 months ago so software probable upgraded since then.

All I would say is make sure you have a backup plan in case it doesn't work....!