Trouble with microsoft combat flight simulator now that I have windows ME

Recently my home PC has been upgraded to Windows ME, from Windows 98. Ever since, I can not use Microsoft Combat Flight Simulator. The Frames per second are down at 2.5 to 4.0. This is a very choppy condition to fly in. It is not enjoyable. The PC is a Intel celeron 233 processor. 128 megs of RAM with a 2 gig hard drive. Before loading the game I have almost 700megs available and around 500megs after it is installed. I've upgraded my directX to version 8. The Video display adapter is by S3 Inc. ViRGE/DX/GX PCI.
I've tried running with and without hardware acceleration and it does not seem to make any difference with regards to the frames/second rate.
Can you tell me if my computer is not equiped to run at a better frames/second rate, or is there an upgrade I can input to improve. As far as I know my PC excedes the minimum requirements for running this game. I'm quite disappointed
Thanks for your time.