OK, this time I have a fix to share instead of a problem.
Maybe most of you aren't affected, but if you are, here's what I did.
If you're running onboard INTEL video, be aware that there's a hotkey that rotates your screen. Unfortunately, in MAME, that equates to CTRL+ALT+any directional arrow. When you hit this (I did on Aero Fighers), the game will lockup. It appeared as if Win 7 had crashed, but after some experimentation, I fixed it and found that it was the screen rotation that was causing the crashes.
Right click on your desktop, and under graphics options, then hotkeys, select disable. I can only assume that onboard Intel graphics are affected.