This has been happening since the release of SP1 for Windows 7. I don't know if it is exactly that update, but it is one of them that causes a blockage of software adding menus to your context menu. The software that I'm having issues with is PowerISO and Unlocker.
This is a pain in the ass because now I have to restore to before SP1 was installed and it takes forever to reinstall SP1 with updates. Please fix this.
I have installed all Microsoft Visual C++
20XX Redistributable Packages and Microsoft Visual C++ 20XX
Redistributable Package SP1 downloads.