Renoise Freezes?

Whenever I leave renoise running for a while, and then come back to it, it decides to lock up. I can click on the buttons and even scroll, but nothing will play. This always occurs when I go away for a few hours.

I’m using WinXP.

Any ideas?

Some VST effects lock up the computer for me gradually. Hitting the “panic”
button in the top left always clears it for me though.