ahh the fun of Firefox!.. when i open many Firefox windows and tabs, things start to lag badly, checking the task manager its usually will consume 1-2GB of ram and some unknown processing 1-2 cores at behind, maybe some scripts not sure. the fix is simple "End Process" button and restart then carefully select out the unecessary windows. its clean again until i reopen another many windows/tabs. Chrome shows much much more stable operations but some websites will show errors when Firefox still can open them. both are old unsupported version in WinXP though maybe that explained failed to open scenarios in Chrome (unsupported certificate whatever it is), so i use both to save one another's arse, mainly Firefox (albeit its unstable nature) due to easy GUI to save bookmarks and shortcuts buttons etc. anyway they are not like working on critical project files that need saving from time to time, so its not critical, just end task and restart. and the wonder of both is i can start again to where i was even on power outage, so browsing experience is uniterrupted with many power outages, hibernates cycle for many many days. the time when i got "Windows resource depletion" warning is when i open all chrome, firefox, photoshop, altium, autocad at one go, but it seldomly happened and i trained myself to make a habit not to work on many unrelated projects at a time.