I'm running Firefox 16.0.1 and Thunderbird 17.0.2 on 64-bit Windows 7 Home Premium SP1 on an HP Pavilion desktop with a 2.70 GHz AMD A4-3400 APU and 4 GB RAM.

After downloading and installing ZA-free 11.0.768.000 without anti-virus (I'm using Microsoft Security Essentials) I discovered that both Firefox and Thunderbird would fail to load completely. On entering Windows Task Manager, I would find both applications in the process table. Attempting to terminate these processes manually would fail to complete. With the Firefox process, I would sometimes get a message box saying I did not have sufficient permission to complete the requested action.

Complete un-installation of ZA and re-booting returned both applications to their normal behavior.

I was wondering if anyone else had encounter this problem and how it might be resolved.

Thanks in advance for any advice.