3d accelerator card not detected

I’m using win2k on an athlon pc. I was using
an ATI all in wonder 128 pro video card. It was working fine, then it suddenly is no longer recognized. I changed it out with a diamond card which was working fine in another system and replaced it withthe ATI.
Results neither card is recognized by the Athlon system as 3D capable yet both perform flawlessly in the other system. I have no idea what may have been changed to cause this. I had an apprentice working for a while
She sownloaded and installed all manner of things while I was out of town. I discovered this after she had left to seek fulltime employment. Has anyone experienced anything like this?