My computer got so slow that the mouse was slow and jerky and I had to reboot. System interrupts was at about 30% CPU time. My PC is now with 5 days uptime and the bug seems to have disappeared. The following solution seems to solve the issue :
1. Right-click on the speaker icon
2. Select playback devices
3. Click on the speaker properties
4. Go to the enhancements Tab
5. Click Disable All Sound Effects
6. Click OK. You're done!
The sound enhancements seem for some reason to cause the problem even when not used. So disable them following the procedure above. Good luck!
[Christina Komninou is an electronic engineer and a programmer]