- Check your cable connections.
- Increase the amount of RAM allocated to the program. Quit the program, find its icon in the Finder, click once on it, choose FILE:Get Info, and adjust the Preferred memory amount.
- Rebuild the desktop (restart with command-options pressed until asked if you want to rebuild desktop. Click OK)
- Run Disk First Aid or Norton Utilities.
- Zap the Pram (restart with command-options-P-R pressed until it chimes three times and then release)