Computer Slow Down/Re Activation Problems

I'm not really a computer noob ( Building a new rig in the next month or so hopefully) but today something really strange happened. It came up with a message at the XP welcome screen saying:

"Your computer hardware has changed substantially since first installing XP, You will need to Re Activate it within the next 3 Days"

Those weren't the excact words, but the main problem is my Hardware hasn't changed for at least 6 months and the only thing I ever changed was the GPU. Why is it saying that now? Could it be linked to a Harddrive problem which is on its way out (As I will explain later)

So without futher ado because I was in a hurry I activated it again, no problems here it seemed to activate fine.....

Next big problem was when I actually loaded into Windows it was running soooooo slow... The Harddrive was on fulll whirring constantly! Everything went so slow it too about a minute to load up Outlook (Normally takes like 5 seconds). Is this my Harddrive Failing/Registry Mess Up/Viruis???

Thanks in Advance,

Tim

Not sure about the performance thing but if it asks to be reactivated just do it online or give MS a ring, the details should come up on screen when it asks you to reactivate.

Yea it reactivated fine I was wondering why though...

Have you tried booting into safe mode and seeing whether the HDD problems are still there?

Could be harddrive problems. I usually get the activation message when my NIC dies/changes, as it counts for more points towards the activation.

Try a chkdsk?

Check your device manager for any problem devices - if the driver for a component fails then windows thinks you've changed your hardware.