Russ, I'd suggest doing a reinstall of Windows...
I use a 5-year old dual-core AMD powered (low wattage) 11" netbook. I've been very strict about what software is installed. It has 4GB memory and a 320GB hard drive. Doesn't miss a beat, and doesn't chew through power like faster machines generally do (unless you buy the latest ultra low power chips). I run APT, PHD2, EQMOD and Canon DPP, the only time it seems slowish is when I double-click on a raw image to get the full size and it has to debayer the image, but it only takes a few seconds
