Thanks for the screenie, scottiesmum.
You have a huge number of processes going on (54) and I'm sure that a lot can be switched off without causing harm.........as a comparison, my XP system runs with only 29 running.
It will take me a bit of time to sort out those that can be stopped safely....will be back.
In the short term, and if I were you, I might be considering a change of browser.......your firefox and it's associated plug-in container .exe is gobbling 226.068 of ram and added to that you have msnwimext.exe taking another 47.112 just to put either an msn or a Bing toolbar into your browser.
That's 273 ms of ram just to run Firefox......my wee Opera is currently using 66 ms.
Will run through the others and be back.
edit to add.....to clarify how much ram is installed go to your "My Computer" icon on the desktop, right-click and select the properties tab.... the amount of installed ram is shown towards the bottom right.