Explorer.exe 100% CPU

Here's the best way to do it:

click Start>Run and enter regedit

You will navigate to the following key:

HKEY_CLASSES_ROOT\SystemFileAssociations\.avi\shellex\PropertyHandler

by clicking the + signs beside

Hkey_Classes_Root
SystemFileAssociations
.avi
shellex

>> then select (highlight) PropertyHandler

>> next Click File > Export and give the file a name. Then export (save) it to a convenient location before deleting it. It can be restored later if necessary by clicking the saved .reg file

>> after saving it, Right click on the PropertyHandler folder in the left hand pane and select "Delete"