What graphics card? If it's a GeForce 4, you may want to get a copy of GeForce Tweaker and underclock by 10 or 20 Mhz. After accepting the recent Windows Update v4, my GF 4 Ti 4600 lost the ability to run DB programs (and anything else that used DirectX 8 or 9), and underclocking the 4600 was what finally worked.
System Restore didn't help; neither did formatting my hard drive and reinstalling Windows XP, because #%$*@! Microsoft wouldn't let me get any updates unless I accepted the v4 update first. It's been a real nightmare. I still get lockups in DBP programs that worked fine before, but at least some of my older stuff runs okay now.