For some reason Firefox has been acting very strange lately. It began a few days ago while I was browsing. I noticed in Networx that something was using up all of my bandwidth and Comodo told me that Firefox was using 99,8%. I was just watching a video on YT and according to the bar the buffering was done. I closed the tab, but the download kept going until I closed FF completely. This same thing has been happening every few hours since. The first day Networx told me I had downloaded almost 10 GB, while I had only been browsing these forums and watched about 10 videos on YT (in 360p). I thought I had solved the problem by uninstalling FF and running a portable edition, but I just noticed it happening again. In just a few minutes it gobbled up over 500 MB. I've already done multiple virus scans, which turned up nothing. I always seem to detect it when I'm either on YouTube, or on a page with embedded YT videos, but this could just be a coincidence. My disk space also remains pretty stable, so I have no idea what's happening. Any help?