For future reference to the original poster and other lurkers, when people ask for system specs, the CPU speed and amount of RAM are among the last thing that's probably causing the conflict in question here. Video and sound card are critical components that troubleshooters need to know about. Operating system is also necessary.
Sounds like this issue might revolve around some background program interfering. I'd hit Control/Alt/Delete and take out any unnecessary background programs, disable any virus scanners, schedule planners or any crap in the system tray. Run Ad-aware and Spyboy S&D to clean out hidden programs running in the background. Then try WC4.