The CPU Usage is constantly above 30%, look at the task manager screenshot below. The strange thing is, I'm not doing anything different than I did, say, last year. The programs running are generally the same and the CPU usage was always under 10%.

I've ran 3 different virus/malware scans: NOD32, AVG, and Malwarebyte's. They found nothing, except 1 weak trojan, but that's all. The computer is still functioning at the same speed. Anyone have any tips? I was thinking about re-installing Vista completely, but I don't really want to do that.
EDIT: Here's my computer specs: HP a6118x