So I recently upgraded the video card in my windows98 PC to a GeForce 6200, and ever since then every time I shut it down I get this weird error message:

Windows protection error. You need to restart your computer.

Press any key to continue.

My pc functions normally otherwise, I'm just wondering what is going on?

EDIT: If I press a key, it shuts down normally. If I leave it alone long enough, it shuts down normally. If i restart the computer, nothing much happens.