Installing is insanely slow

Ok, ive been having this problem for a while, nothing wrong with win 7 but say i download a trial for say Adobe After Effects. when i click to open up the installer it will take anywhere between 5 and 25 minutes to JUST OPEN THE INSTALLER omg this is so annoying. AE itself (the entire program) installed in less than 2 minutes but it takes crazy amounts of time for installers to show up. my entire pc runs fast for everything else, browsing games etc but this is the one thing that is veeery slow. whats going on here.

Check the Event Viewer>Admin view for logged errors at the exact time this hang occurs.

Test your memory with Windows Memory Diagnostic Test for two passes.

To further clear hardware, test your HD using maker's Diagnostic/Repair full CD scan: http://www.tacktech.com/display.cfm?ttid=287

Run sfc /scannow to check integrity of System files.

Short of reinstalling the OS, you can run a Repair Install

But there may be those who are expert with Windows installer who can give you more specific fixes.