explorer.exe using a lot of CPU (80%-95% constantly)

Even when I have all of the programs closed, the process "Explorer.exe" is running at 80% - 95% all of the time. This is causing serious system slowdown. Any ideas?

I just recently recovered from this.

Apparently, there was a file in one of the recent folders I downloaded from a client that was corrupt and it was causing the issue. Look for a file that you recently received or downloaded and move it to a USB stick then delete the file from the local HDD.

If that doesn't work, turn off all services that are non microsoft, and turn off all startup programs using msconfig.

You can also try turning off windows search from services.