Disable all non-essential system apps
Before recording, hit control-alt-delete and 'end task' on ALL listed programs exept systray and Explorer. Note: You may have to hit Control-Alt-Delete multiple times to remove them all. That will eliminate all of the background garbage that hogs resources. Also, if you have >64MB ram, I strongly advise you switch your system over to a network server, even if you don't run a network, because it will increase the availability of file handles and improve disk caching and overall system performance. You do this by, in the Control Panel, double clicking the 'System' icon, then clicking on the 'Performance' tab, then clicking the 'File System' button. In the dropdown box, select 'Network Server' from the list, hit OK, then reboot. That's it!