MMC Console Restricted access?

I have just recently been thrown in the deep end! Our network administrator has just abruptly left for various reasons unknown and I’ve been handed the position on a trial basis, Unfortunately I’m struggling already, On one of the workgroups I have logged onto several of the machines to make a few adjustments only to find I have no access to the MMC, My Computer properties, The start menu Settings or Run. I have tried various tricks and fixes but I am making no leahway, I also have to tread with caution as it appears that none of the data (which is ultra important)has been backed up on this workgroup.
Would promoting one of the good machines to a PDC do the trick? or has anybody got any better ideas/fixes? anybodys help would be greatly appreciated!