I've had this problem on and off with Vista and Windows 7.
I did some searching around the internet and one train of thought reported by several people was that it was caused by incompatibility between the operating system and some shell extensions that software may have installed.
These extensions are the things that give you a variety of 'options' when you right click.
Windows puts it's own in, which are OK, but so does a lot of the software that we install and with many you don't get the option not to install the shell extension.
For example; 7Zip gives an option to 'extract' a zipped file when you right click on it.
There is a little 'freebe' application that reveals all the shell extensions that are installed, and gives you the ability to 'disable' - or 'enable' - the extension.
I would look to the ones placed there by software not related to the operating system and 'disable' them one at a time until you find the one(s) responsible.
My problem was (is) associated with a programme that I use a lot and therefore I left it 'enabled' because I prefer to have the functionality despite the ocassional 'crash'.
It can be a bit time consuming to find the 'problem' one, but it is easy to 'enable' them again so there's no permanent damage done.
See link for application.
http://www.nirsoft.net/utils/shexview.html
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A pessimist is simply a realistic optimist
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DrayTek Vigor 2710n