Hi! I just came across this post and noticed there are a lot of 32 bit processes. Is the operating system 32 bit? Is the system seeing all of your RAM? It seems like you have quite a lot of programs running at once. If the system is 32 bit or doesn't see all the RAM for whatever reason, compounded with the number of running processes, then it may be running out of RAM and using the HDD for virtual memory.
As far as I understand, the licenses for Windows works for 32 and 64 bit, so if you need to upgrade you may be able to find someone with a 64 bit disk and still use your key if in fact you have a 32 bit version. I would go through all of the programs that hide themselves on the task bar and disable anything starting up with the computer unless it is absolutely critical. You may even have to take more drastic measures to ensure things aren't needlessly starting on their own.
Just a quick rant: I despise programs that have install options such as Express Install or Advanced (for experts only), then you click on advanced and find out all the extra options are malware/bloatware/needless garbage that auto starts and bogs down your computer. I really don't miss Windows at all. (/rant)
When using Firefox with a bunch of tabs open, lots of little things will eat up resources, such as anything involving Flash. I tend to bookmark things a lot to help reduce some of the need for so many tabs. Also, changing the advanced option to save and quit is a giant help! Go to about:config in the address bar, click to continue, and scroll down to browser.showQuitWarning and change to true. This allows you to save and quit when you close the browser. When you restart Firefox, by default it will only load tabs when you click on them. If you have 10 or more tabs open it is a good idea to take a couple seconds and do this to stop Firefox from hogging resources. If you start to notice slow downs or weird text issues while web surfing, this almost always has fixed the issue for me.