I’ve had this problem occur on two PCs so I thought I would post the fix (courtesy of Brian Keller) since I’m likely not the only person running into this.
Go to this page to install Flash (uncheck Google Toolbar, no idea what that has to do with Flash)
You’ll get a confirmation screen that will say it’s successfully installed, but you still won’t be able to watch videos on MSN, YouTube, etc
To fix, Run C:\Windows\System32\Macromed\Flash\FlashUtilXX.exe where XX is the largest value you find in this directory. (For me it’s 9d, but it used to be 9b)
You’ll be prompted to close all browsers and you’re done
**Updated Jan 11th for Windows 7/Internet Explorer 8 64-bit **- Go to the directory C:\windows\syswow64\Macromed\Flash\ to find the FlashUtilXX program.