I need help please. Some problems with windows/new PC. thanks.

Hello all,
I bought a rig about 3 months ago.
System
Q6600 /true120
Striker II formula
4gb kingston hyperx 8500
evga 9800GTX
ocz ssd core 64gb
320gb hitachi SII
1000W PSU (for future tri sli)

Bought an oem xp home sp3(what he told me I got), the dealer installed on HD, not a good job, I reinstalled, then did new install on SSD, then did RF and new install on SSD. When I cam to authenticate it all, it asked me for a new key as my old one is no good..
how is this possible? I'm only using this on this computer..

thye 2nd problem i'm having is I can't load into windows if I don't have the xp disc in the driver. It does the "press any key to continue" which I don't touch and then loads up. Otherwise it will sy "boot failure, drive not found" or something like this..if anybody knows anything please let me know..
Any help appreciated!

I need to activate it within 30 days and it says my key is no longer good:"according to our records,the number of time, u can activate windows with this product key has been exceeded please enter a different product key and click retry. the 26digitkeycan be found on the COA label attached to your computer or windows documents"

It needs new enter of key, but mine is new...I bought this for this specific pC and only this..
thanks for the reply.