|I have quite a few old DX7-9 games that run fine under Win7. |
Install the latest DX9c pack from MS (the first link X86 gave you). That fixed most of the issues my old games had under Vista and 7.
Super PIII | Unlocked ES Tualatin @ 1.8GHz (150x12, 1.65v, 512K L2)
2GB PC2700 | 500GB | Radeon x1950Pro | Apollo Pro 266T | Win 7 Pro