don't give up yet bro while a reformat MAY be in ur future...there still the thing about the game itself..I had a similar problem with Knight Online another free MMORPG :/

Downloading the game from a mirror caused not only comp problems but also wanted credit card number etc... try re DLing the game from the Shaiya site itself ...TOTALLY uninstalling it...including do a regedit search for the words Shaiya and w/e the .exe file is called for that game. Then try reinstalling Shaiya DL'd directly from their site.

One question...did the game EVER work correctly? And if so, do you know of anything that "changed" right before it started giving you problems? Like maybe, installing some other software or maybe moving the computer..too roughly? With that stop code it almost HAS to be a memory or vid drivers error....I guess it could be a Windows error that is causing it, but for the life of me I can't think what it might be.

You had said that you also down graded from Vista...did the game work before that (did you even have it installed on Vista?) Like someone mentioned there have been a zillion issues with some comps and trying to downgrade from vista.

If the game has never worked correctly..then it may just be a left over downgrade to XP issue....However if it DID work correctly at one time...then you probably dont have to reformat.