That was quick! You have arranged by memory rather than CPU....looking down the CPU column nothing is taking any significant %, unless it is off the bottom.
You aren't atcually running very much - Firefox, Internet Explorer too (2 windows as well!), Irfanview, Nvidia control panel I think...I guess the av*.exe is some sort of antivirus. The svchost.exe processes are to run NT services, these are programs that run in the background as soon as you start the computer.
FYI, I am running far more than that on a Pentium 2 300MHZ with 192MB of RAM and response is good even though CPU usage is up at 100% at the moment due to a big WinRAR decode.
Sort by CPU, and tell us what happens to this list when you start one of the programs (and do you HEAR a lot of disk activity?).
I am going to get something to eat now, will be back in an hour or so...