XP not validated

Power interruption required PC restart. Got error msg that OP installed is likely illegal.
Lost screen background, msg keeps popping up that this version of XP may not be valid. Bought this computer used with XP loaded.
Went to MS site to see what was needed, it referenced WGA Plug In Installer.
That failed, citing error 0X80070003 and referencing MS troubleshooter to remedy problem (missing or corrupt files) Firefox plugin had failed also.
Trouble shooter did not accomplish anything.
Found multiple programs that will "fix" my problem (or at least this one) so I can continue to solve the other 999 problems I am having.
However, they all contain warnings about "fixing" the registry.
Whiskey Tango Foxtrot?
Am I doomed to logging on daily only to find yet another glitch?
What a revoltin' development dis is! I am spending all my time chasing errors!

 

It sounds like the Registry hive was corrupted by the power outage. Do you have an install CD? because it looks like you need to do a clean install. The first few updates would include a permanent copy of the Package Installer and WGA. All of the updates through and including those available on 4/8/14 and the "emergency" update that was given a short time later are still available.

 

I would try the easiest solution - revert to a saved Restore Point. Next I would do a SFC / SCANNOW to perhaps heal any corrupted system files. Then I would try tweaking.com, step by step. Finally there is the factory recover option.