FSX locking up during install

Having upgraded my PC specifically for FSX I am somewhat bemused why my PC keeps freezing during install. Since purchasing FSX I have updated the drivers/bios/directx/windows, hdd defrag, turned off Anti-virus/Firewall etc used msconfig. As a last resort I sent away my PC for a hardware checkup/Vista upgrade. The Power supply, memory and Video card are all performing without fault, so what does one have to do to play this sim? Am I missing something? P.S. I managed to play FSX on the same PC using Windows XP (at 40 fps) yet it did freeze regularly in mid flight and also whilst re-installing. I had hoped Vista would solve the problem. Any advice would be appreciated. 2Gb Ram Pentium 4 3.40GHz, Dual Core 200gb HDD Nvidia GeForce 7300LE Windows Vista Home Premium