Change Default Application For "All" Isn't Permanent

Hi,

I attempted to search for this problem in the forums but don't have time to drill down and that's why we are all here anyway (i.e. to help each other) so here goes. When I change the default application by clicking "open with" and then specify Adobe Reader and then click the "change all" button, PDF's will open with Adobe Reader until I reboot. Then I have to repeat the entire process.

What am I missing? I have done this like 30 times & can't find any documentation that describes the issue. I Googled the issue but didn't get any hits so I'm not sure if it's a known glitch or if I'm just being a blonde.

Thanks