The 6200 is a budget card that, although is listed in the supported cards, needs a decent CPU to back it up. Also, if you are running the bare minimum memory specified, you're going to get a lot of virtual memory usage, which will slow things down. So, I'd start there with trying to smooth things out by killing unnesesarry apps.
As RR brought up, check and see how many memory resident apps you have running in the background and turn off the junk you don't need (start with the apps in the tray on the right side of the taskbar). As an example, on my old PC I have to turn off the junk, and even the firewall and virus checker, if I want to get BoB II to run nicely.
There are also a host of Windows services that you could and actually should turn off as they are a security risk for a home PC. Here's a good walkthrough on how to do it and what to turn off:
http://www.blackviper.com/WinXP/servicecfg.htm
Getting rid of all the junk will 1. free up memory, and 2. free up CPU time, so it should help with your performance.
You may also want to download RivaTuner and see if it's possible to overclock your video card slightly.
Once that's done, defrag and compact your hard drive. Here's a free version of software that will do both MUCH better than the windows defragger. First you run defragment, and then you run compact. It will speed up your virtual memory usage:
http://www.dirms.com/
BTW, if your free hard drive space is getting low, that will slow everything down long before windows ever gives you a warning.