Why is XP Home asking to be activated?

HP tower with XP Home SP2 preloaded. The DVDRW died and I just replaced it about 10 minutes ago. I powered up, and Windows is saying I must activate before I can log on?!?!?! WTF?!?!?! Why? I've installed dozens (if not hundreds) of optical drives and NEVER been forced to re-activate. No other hardware changes were made and the date in the BIOS is correct. It's not a big deal, the Windows is legit and the key sticker is here and it's all 100%, but it's just freekin' weird.
:confused

Any input or thoughts on the situation are welcomed.

[dlb]

 

As I suspected, I was able to activate without any issues. I thought maybe the Windows time/date may have been wrong, but it was correct. I guess this is just another one of those bizarre Windows happenings.... not the first, and I'm sure it won't be the last

I'm still wondering if anyone has any thoughts on why it would ask for activation. I had been using it yesterday and it never once prompted for activation or did it say "there's 2 days remaining before you must activate" or any of that.... no little set of keys down by the clock either.... odd that installing a DVDRW would trigger the oobe timer...

 

i installed a chipset driver and it said I needed to reactivate which was kinda stupid but .....well it's microsoft.