Check the Temp Audio File location, maybe it is getting full.. or has a problem.
Options - Preferences - Audio tab

With MME the buffers and stuff should't be an issue, but also make sure the correct audio drivers are being used (not Soundmapper or such) as another test.
Options - Preferences - Audio tab - Drivers button (look at input)


I do not work here, but the benefits are still awesome
Make your sound your own!