Do you have a Microsoft Windows PC running slow? The first but usually most painful solution is to reformat and or reinstall.
However before proceeding with such drastic steps there are two things I recommend checking:
1) Do you have enough physical memory? You want to reduce the frequency of virtual memory paging activity. Run Task Manager by pressing CTRL+SHIFT+ESC. See below:
*Note: If you have Windows Vista or 7 remember you can add additional member on the fly with a USB stick by using ReadyBoost
2) Make sure your hard drive(s) is running in DMA mode. It is unfortunately not uncommon for Windows to revert to PIO mode which means transfer speeds of 3-4mbps instead of 50-60mbps. Basically remember that PIO=slow, DMA=fast. Open Device Manager by pressing WinKey+R and typing “devmgmt.msc”