OK. It looks like you may haveassociation problem. You can fix it up manually, but easier to go here and select the "msc" option.
Link Removed - Invalid URL
It is for Vista, but it's the same thing.
If that does not work, it can by a myriad of different things, but, fwiw, make sure you have the folder Users -username-Appdata - Local - Temp , intact and have not accidentally deleted it. (Or, If you have it, delete the entire contents -don't worry, it will do no harm)