This is almost the same problem I am currently having atm. I just switched to win7 pro, and want to play ArmA again (played it fine on my old XP install), patched my Gold install to 1.14 and it crashes no matter what I do. I tried patching to 1.15beta and also msconfig trick to limit sys memory to 3GB and still no luck.
I am running AMD Athlon 6000+ AM2, HD4850, on Win7 pro. Drivers are current to my knowledge.
HELP!
Edit:
Issue is ArmA freaking out over too many sound options. Disable all other sound devices before you play and no problems! Thanks to GossamerS on thiis fix!
http://forums.bistudio.com/showthread.php?t=91133&page=2&highlight=windows