Installation failure sp2

After building my new comp I installed all my drivers (except for raid driver). I cannot install sp2. Every time it will complete the download of sp2 and then it will say that it has failed to install. I've tried downloading the whole sp2 package elsewhere and it gets corrupted. I've searched my computer for bad spyware and found some and removed it, but it didn't help. Under my 'update history' it tells me the failure was because of error code: 0x80246002. any ideas?

Where did you purchase your copy of XP? The 0x80246002 error code is a validation issue.

The cd came from some laptop we had but no longer works. It's a Dell xp installation. I validated my windows so now i'm really confused.