FSX Acceleration Problems

If someone could help.
1.Prior to installing FSX A instant replay worked. Since the installation instant replay caused the my system to crash.
2.After flying a plane from FSXA planes from FSX do not show up unless you exit the game and start it up again.
System
Alienware M9750
2 G Ram
160 hd
Intel dual proc. 2.0 gh
Nvidia 7950 gtx sli
All drivers are current

Thank you