BitComet 1.20 ADSL2 Billion 7404VNPX UPnP WinXP AVGFree 9.0.801 Teamviewer 4.1
I upgraded from 1.16 to 1.20 a few days ago, but whilst operating on a largely unattended remote monitored machine, traffic ceased and the process was consuming all available time with no window repainting.
Killed the process and restarted BitComet, but the new process continued to soak up all processor time with no window appearing and no traffic.
I reverted to 1.16 by reinstallation and problem went away.
I had a similar problem some months ago upgrading from 1.16 to 1.17, and sidestepped such a problem by returning to 1.16.