After your scan, run Task Manager and click on the Memory Tab to see which process are eating up your memory.
After that, try downloading and running FireFox to see of there is problem with your IE9.
Also, as a precaution, download HWMonitor to check your CPU temperatures. Your machine should be idling between 28C-42C depending on the cooler and CPU.
You could very easily have a CPU that is running hot because of hardened heat sink grease and that would really slow your system down as the CPU gets hotter..
If you boot into safe mode and do not see a performance issue, then it is not a hardware problem.
BTW, I went back and reread you have a AMD processor, so your idle CPU temps will most likely be 36C-48C. Hardware Monitor is a free and good tool that lets me know when I need to blow the dust out of my systems plus I have had to reseat a CPU on another system with new heatsink grease about a year ago.