Virtual memory is another word for disk space.

No offence, but from the FAQ master I think that's a pretty average answer.

Virtual memory allows a program to use more memory than is physically available. Physical memory is actual RAM. Basically virtual memory is a special section of hard drive space (file or partition). When you run a lot of programs the ones you aren't using get "swapped" out to disk temporarily to free up some RAM for programs the you are currently using. When you go back to these swapped out programs, they are loaded back from disk to RAM (possibly other programs get swapped out then).

Un*x type OSes generally have dedicated partitions for this swap space while Micro$oft OSes generally have one large file on the main drive (although it can be multiple files spread across drives). XP for example does have an upper limit on the amount of swapfile space you can have. In the case of my 512Mb machine it has defaulted to a minimum of 384 and a max of 768Mb. A standard x86 PC is limited to a 4Gb virtual address space.

If XP is telling you you have run out of virtual memory you have probably run out of either swap space or disk space although I'd bet that message would come up in the case you were severely lacking in physical RAM too. Eventhough you have closed everything, I'd still recommend a reboot. You'd be amazed what sort things a reboot can fix.

Just because you have enough disk space doesn't mean you can run everything though. If you don't have enough physical RAM and try to do too much, you will get "thrashing" where the OS tries to swap stuff frantically to and from the disk so it can run all the processes. You can't run processes from virtual memory - the process must be swapped back to RAM first.

I would have thought BF1942 would have run on 256Mb but I heard from someone here it's a pretty intensive program and requires a fair amount of CPU/GPU (and possibly RAM too). In the case of a game you probably don't want to be relying on virtual memory at all.

My suggestion is try the reboot with as little as possible running in your system tray (download managers, ICQ, IM etc). Worst case look for another 256Mb stick of RAM. I found 512 over 256 helped quite a bit on XP although I run quite a few apps at once. However I did achieve similar levels of multitasking success on old PC with Win98 and only 192Mb

HTH