There maybe extra programs loaded in memory that are draining your resources. For example both ATI and Diamond load extra program into memory that allow you to access the start menu or video functions anywhere. Unless you need these types of programs you can remove them and free up memory.

You can do this by rebooting, then do ctrl+alt+delete and see what you have running. The only two programs that need to be running are explorer and systray. Most everything else is not needed. You will find most of these programs loading in the start menu and/or in the registry (HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current Version\(all the run entries) Just delete the ones that you dont need. I would write down the shortcuts and backup the registry before anything. This should help you free up some memory.

Also large wallpapers and lots of icons on the desktop can kill system resources also.

One final thing, I have notice that any program I make in VB that does alot of memory intense things will drain some resources each time I run it. I now have the resource meter running all the time so I will know when it is time to exit VB and when to restart my machine.