Lag Spikes

Maybe defraging your hard drive or running maple from a USB stick (one that reads/writes faster than your hard drive) would help.

My hard drive is near-empty and has been empty since I reinstalled my computer. I now save almost every single file I use on my desktop. It's mostly pictures, word, excel, or text documents. After I finish working on each file, I move it to an external HD, which I keep unplugged. For that reason, my computer has 94% free disk space and is always defragmented completely.

Since I still get that annoying lag every 15 seconds, this definitely isn't the case. At first I thought it was a keylogger, but then I saw this thread.