If you did not do this already you should change the default allocation of virtual memory under Vista - the default 2GB system / 2GB application does not work well with FSX.

Assuming that you have a 512MB graphics card, try this:

* Open a command prompt with administrator rights ("Programs" "Accessories" "Command prompt" right click and select "run as administrator")
* Enter "bcdedit /set IncreaseUserVA 2816" (without quotes) in the command window and press enter.
* Restart windows

Now try your flight again and see if the problem is solved.

If you have a graphics card with different size memory, you should calculate the value to use instead of "2816" as 4096-(768+graphics memory). Eg with 256MB graphics ram you get 4096 - (768+256) = 3072. This leaves a reasonable amount of virtual memory for the operating system.

This change applies to all programs running on your computer, but only some applications can take advantage of the additional virtual memory space. If you run into problems you can always revert to the default be using the steps above with the default value of "2048".

Btw, this is regardless of the amount of physical memory installed - with 2GB physical memory you still have 4GB virtual memory.

Good luck,
Tom