A few days ago, trying to free up some memory and improve my computer's performance, I deleted the cache and tracking cookies from Firefox (using AVG TuneUp). Since then, I can only load a certain, variable number of tabs and/or pages without every new or reactivated tab or page claiming to have crashed (although about:crashes says that no reports have been submitted). Restoring those pages seems impossible without restarting Firefox or the whole computer. The problem persists in Troubleshoot mode, but as far as I can tell doesn't affect Chrome, although that used even more RAM. I've tried culling open tabs (of which I still probably have far too many, but it's never been an issue before), using the OneTab extension to reduce them to lists of URLs, disabling and re-enabling hardware acceleration, updating Firefox, checking for file corruption and RAM errors and even uninstalling and reinstalling the program, but nothing's worked so far. What might be going on, and what else can I try?