I've been using Sitehound for over a year without incident. The other day, I rebooted the computer, and afterwards neither Firefox nor IE7 would open a window. I tried opening Firefox in safe mode and it worked fine, so I disabled all my add-on programs. After that Firefox worked in normal mode. I enabled my add-on programs one at a time looking for the culprit. After I enabled Sitehound, Firefox would not open in normal mode. Next I disabled all add-on programs except Sitehound to see it there was an add-on conflict. There was not. It would not open in normal mode with only Sitehound enabled. I deleted Sitehound from Firefox and reinstalled it. The error repeated, so I deleted it again.

Next I uninstalled Sitehound from IE7, after which IE7 worked properly. I reinstalled it, and IE7 would not work again. So I uninstalled it.

Both browsers will now work only with without Sitehound.

Any ideas? Thanks in advance.

Their update server was down. While that was out of commission, numbers of users experienced the same or similar issues, although some didn't. Why the difference? The servers are back up again so you should be able to reinstall it and be fine.