I believe this is caused by a lack of memory on the system.
Click on "Start"
Click on "Run"
type in "winmsd"
it should tell you total and available physical RAM. the first should be roughly 256MB if you are running XP SP2. Available, I normally say should always be higher than 128MB, if it is below then I would recommend upgrading the Total Physical RAM to 512MB or Higher. For this I recommend speaking to trustworthy computer technician.

please note: if you are running Windows 98.
Click on "Start"
Click on "Programs"
Click on "Accessories"
Click on "System Tools"
Click on the icon "System Info"