This problem lies within a relatively fresh x64 Windows 7 install ~4 weeks, but is also a problem I have seen on Windows Vista machines (x86 versions).

Since the other day, any programs attempted to be launched via right clicking on a shortcut (.lnk)'s context menu and pressing -> "Run As Administrator" for instance, in the Quick Launch/Jump List in Windows 7 has failed, screen has not dimmed, no UAC popup. In fact the program does not even load. There is no way around this unless I use the shortcut version from "All Programs" which appears to work, very strange? I have performed no major software installs, nothing out of the ordinary.

Has anybody encountered this or know what would be causing it?

Here's an example of somebody else experiencing this problem in Vista with no solution: http://www.vistax64.com/vista-general/131918-strange-run-administrator-problem.html
and I believe this problem is related, I also cannot right click -> "Manage" on my computer): http://windows7forums.com/windows-7-support/5501-run-administrator-broken.html

I am running the latest version of Avira AntiVir Virus Scanner and pretty concious of what I download, I don't think it is a virus, nor do I believe it is due to the RC Version of Windows 7, because I have seen the problem across multiple Operating Systems versions.

Thanks guys.