Computer certificates are kept in Registry in
HKLM\Software\Microsoft\SystemCertificates\My, which you must have read/execute permissions on.
At least on Windows XP, members of the "Users" group have enough access to read the
Certificates subkey, meaning you just need to add the Certificates - Local Machine snap-in to MMC. Since MMC doesn't want you to do that, create a MMC console on another machine. (Here's the one I use. If MMC 3.0 consoles are incompatible with Windows 7, you'll have to create one on your own PC, then carry it over.)