Sims 2 conflict

Installed Sims 2 on Dell Dimension 8400 about a year ago.  It worked fine, but about a month ago, the display vertical lines appeared on screen, and a system error -- device failure would appear.  Would have to restart game.  Then another message came up:  Could not find any compatible Direct 3D devices.   Diagnostics checked out that all devices and DirectX was fine.  Anyone else have a similar problem with video games, and is there a fix?  No problem with any other apps.