I have a computer running Windows 7 Professional 64-bit. It has a single account with admin rights. I don't really know when and why this happened, but I can't perform any admin task anymore:
Each time I try to run a program, e.g. Program.exe, as an admin, I get this error:
Windows can't find 'C:\Path\to\Program.exe'. Check the spelling and try again.
When I try to run any software installer, I get:
ShellExecuteEx failed, code 2. The system cannot find the file specified.
Googling this message finds some results, but nothing helpful to me.
Clicking any admin task (with the shield icon) in the Control Panel either fails silently or produces a
Windows can't find 'xyz'. Check the spelling and try again.message, so I can't get important (according to Windows) Windows updates, create a new account, etc.
I ran a Microsoft Security Essentials (which apparently is up to date) check, I can't install new software (such as CCleaner) nor launch a command with admin rights.
Do you have any ideas about what to do? Thanks in advance.