I've found a very annoying bug. After using Vegas for a while, it will sometimes stop playing the video clip I am working on in the preview window... space bar, enter key doesn't play, the play button won't either. I have to close and restart to fix it. I have Windows 98SE w/ all updates installed. The rest of the program works fine- I can even step through individual frames w/ arrow keys, but it will not play anything! Help!

Edit- relevant system specs:

512 mb DDR PC3500
Athlon +2800
Asus A7n8x deluxe v2 mobo
Geforce4 ti 4200 64mb, driver version 4.14.10.4523
DirectX 8.1a
40 gig HD (master, w/ system files)
120 gig HD (slave, video editing files)
Swap file set to 512 mb on system drive
File system set as network server
No programs running in background