In Device Manager uninstall your display adapter then install the onboard video. Reboot computer.
But before you do all that. Most computer hardware is backward compatible. Older programs should work fine with the newer hardware. However, the software side may give you a headache.
Windows is kinda picky about software. If you have WinXP you can set it to emulate older Windows OS's (95, 98, NT, etc.)
Good luck.