fobotcso I believe you are allowed a certain amount of hardware changes to your pc before you have to reactivate XP again (I don't have XP) I think it's 6 items, not sure how changing a HDD would affect this.
StopStart it's not something to be afraid of doing, just be carefull and methodical, and before doing anything backup, backup, backup, the stuff you really need, drivers, documents etc etc.
A work mate recently had a new motherboard, CPU and HDD installed by a so called professional shop.
He kept getting a message that his HDD was only operating at ATA 66 instead of 100. After repeated calls to the shop and after checking his BIOS and numerous other things, he asked me if I had any ideas, I says check the cable, lo and behold they had fitted a 40 ribbon cable instead of an 80 ribbon cable. Professional my rs, I'll have to start charging for this soon!