One of the reasons why you want to keep a live-bootable operating system within one of your flashdrives or optical discs.
You probably need another device to securely boot up a live OS to recover your data. Don’t use Windows, because it might still be vulnerable to autoplay scripts when mounting your infected OS partition and I assume your infected OS is Windows, so the malwares are going to be compatible and unless you know what you’re doing, you probably don’t want to take that chance.
that is relatively low assuming “private bytes” is virtual memory usage. Is that Firefox being idle? How many tabs do you usually keep for your everyday web browsing?