Hey dude, let's try something:
Right Click the installer, find "Properties" at the bottom of the window that pops up.
Click on the Compatibility Tab and look for the "Run this Program as an Administrator" option.
Click APPLY then Click OK. Now double click the installer and see if it works now.
PICTURE LINKEDIT: Can you find the Run as Administrator option on other programs or is this just the Installer that it won't show up for?