It seems to happen for no reason at all, occurring when I'm in the middle of watching a video, browsing the web, etc.
Prior to finding this message board, I had used AVG anti-virus (previously Symantec) to scan my computer, and while Symantec used to find infections every now and then (and would immediately delete them), AVG has found none. I stopped using Symantec because almost every time the program opened for a daily scheduled scan, the CPU Usage would spike and it would slow down the computer to the point of even being able to run the scan at all.
I downloaded the free version of Malwarebytes and immediately ran a full scan. The program found, quarantined and deleted 6 infections. I allowed the program to restart the computer and after doing so, I began to use it as I normally do (surf the internet, watch videos, etc). Everything seemed to be going smoothly, and I thought I had found a solution, until about 10 minutes later and things began to act up again. At one point, my Task Manager "Processes" list looked like this:
Now I don't know everything about computers, but I was under the impression that Windows Explorer (i.e., folders, taskbar and desktop) generally should NEVER be that high. The same thing happens sometimes with the Task Manager itself, Firefox, and some Processes whose nature and purpose I'm completely unaware of, such as "svchost" and "System" (described as "NT Kernel & System).
There appears to be some connection between streaming video and the high CPU Usage, but it doesn't happen only when I try to watch streaming video (although it definitely happens every time I watch a video-- so the high CPU Usage isn't always due to streaming video, but streaming video always causes high CPU Usage).
Sometimes the CPU is able to handle multiple processes at once without so much as a slight hitch, and other times, I can't even watch a 720p HD video in VLC Media Player without the picture skipping and freezing.
I'm running a Dell Precision M6400 with an Intel Core 2 Duo processor and 16 GB of RAM. The reason I purchased such a large amount of RAM was so that the computer could run faster, but now having learned that RAM has almost no direct correlation with processor/CPU power, what can I do to eliminate these spikes?