I'm the only active user account on this machine, although as is the default for Win 7, it's not the Admin account. The uninstaller UAC-elevated when ran.
I got the open beta 1 installer from one of the mirrors on the download page from this site, although I'm afraid I can't remember which any more. Pretty sure I checked the SHA1 checksum, though, since one was provided, and all was well.
(As above, I haven't run the OB2 installer yet. The Start Menu damage was done by uninstalling OB1 manually in preparation, per the advice on the front-page news post. And, yes, I appreciate you're [also] asking Trev-MUN.)