Firefox lags before opening
Starting today, when I open Firefox the button will briefly appear and then disappear on the taskbar. 10 seconds later it will appear again and the browser will open up. I am running Firefox 35.0.1 on Windows 7. My Antivirus is AVG Free (so I don't have any of the browser addons.) The only addons that I have active are AdBlock Plus and DuckDuckGo (search engine.) I've tried deactivating both of these and the issue has not changed. No viruses appear to be present on the computer and no other browser or program is having this issue.
Does anyone know what could be causing this?