explorer.exe consuming lots of CPU cycles on Windows Vista

So, I was having a very interesting issue where explorer.exe was just burning through CPU cycles and it would do this for about 20 minutes or so and then get quiet for about 30 seconds and then start it all over again. I could not figure out what was causing it to eat up so many CPU cycles, so my first stop was to shut down anti-virus to see if this was the cause. So I shut down NOD 32 (which by the way is the greatest Windows Anti-virus you will ever find! I say "Windows antivirus" because I have never used it on any other platform) and nothing happened. Which was good, because this meant that my faith in their anti-virus had never been tested in almost 5 years. So then I shut down TortoiseSVN because that was a shell extension which could be causing explorer to go crazy. And again, fruitless. So, I downloaded Process Monitor (this computer is fairly new and I hadn’t had a chance to download it yet) and found that Windows Vista was trying about 500 times per second to access the Call of Duty 4 Demo that I had downloaded (but had yet to install actually).

It seemed to be trying to get info off of the file and then it was doing this, which is trying to poll info from the registry to get info about the .exe file extension.

So, I deleted the CoD4MWDemoSetup.exe file and voila, the CPU usage instantly dropped and everything went back to normal. What was it doing? I’m not entirely sure, I search around on the internet and found a few people who had kinda similar issues, but not really. I am downloading the demo exe again to see if it starts doing it again and I’ll update this post if I find any new info.