I had BF1942 installed with the Desert Combat mod. It would chop in single player. Pissed me off being a new Dell and all.
Anyways, here is my solution.
When i restarted, I ctrl-alt-del and found that processes on startup were sucking up 190 megs of my 256 ram. I knew this was the problem. After searching and searching, I figured out which processes I could disable and on a restart I know have 120-130 megs free instead of 60 and BF1942 runs fine now.
If you are wondering where to start :
http://www.blkviper.com/WinXP/servicecfg.htm
this site helped me the most.
Then if you have any processes you are not sure of GOOGLE GOOGLE GOOGLE.
Have FUN
ason