Delete of steam.exe failed, Win32 Error 5 Access is denied

After a fresh install of Steam on Windows 7 64bit, I got the following error message when it launched and tried to update itself:

“Delete of steam.exe failed, Win32 Error 5 Access is denied”

After much swearing and Googling, the answer was to turn off AVG completely during installation and update of Steam. FFS.

This thread helped.