I don't know all of your requirements, but for $40 there is the CLearview simulator. Also you have to either buy the cheapy transmitter for FMS or a connector chord for your real transmitter $10 + shipping). You can try it with a DL demo which is actually the full sim, but limited to only a couple of planes and helicopters. The Demo expires after a while. It seems to run fine on my $350 laptop w/ AMD Athlon 1.6 HZ and 250MEG integrated graphics card run by a Windows 7 64Bit Op system.
See link for Windows 7 issues had by others:
http://www.clearviewrc.com/forum/viewtopic.php?t=1032