Just follow what the great Javester says and you should be fine... (i.e. press Win Flag + Pause break key > Advanced Tab > Settings under 'Perfomance' > Advanced Tab > Change ) but... usually all the computers I've worked with that are a little old (with about 256 MB ram) seem to get this error all the time and as a general troubleshooting procedure, I always try what Javester has mentioned, however they seldom work. And they still seem to get those errors. But after install installing about 256 MB ram they seemed to work fine (and faster).

So you still get the error messages then I guess you might want to look at buying some extra ram (I think your system might have too less physical ram right now...like 256 MB).