Vista Program Files Cache when using User Account Control (UAC)

If you're running Vista (probably windows 7 as well) and have user account control turned on, then programs are not permitted to modify files under C:\Program Files or C:\Program Files (x86).

If they do so, the modified files appear instead at C:\Users\USERNAME\AppData\Local\VirtualStore\Program Files (x86)

This drove me a bit nuts as I was using OpenVPN and changing the password on my .key file, I then copied it to another machine and it didn't have the correct password. Aha, I just had to find the file in the VirtualStore cache.