During the quest "No Gods, No Masters", I am unable to complete it as I had already activated the electrical switch much earlier in the game.
Is there any way at all that this can be fixed without going back to a save at least halfway back through my game?

What electrical switch are you referring to? If you mean the control switch at hoover dam this would have been impossible because you wouldn't have had the override chip earlier in the game.

I'm referring to the east electrical switch that yes man tells you to use after installing the override chip.
I didn't know it was for the quest when i activated it earlier in the game, and now it's stuck in the "activated" mode and is un-usable.

From Fallout wiki (bug section):
- The courier is asked Yes Man to pull the lever and activate the eastern part of the dam, if that lever has been pulled in the past the player will not be able to finish the game. :flame: That svcks

Heres the link:
http://fallout.wikia.com/wiki/No_Gods,_No_Masters#Bugs

The door to the electrical switch can only be opened by yes man after you install the override chip in the control room. You say you already hit the switch much earlier in the game.
How did you even open the door in the first place?

did you use tcl to get past the door or unlock the door using console command?

Thanks for the help everyone, as to how i got through the door, my game must have bugged because it wasnt locked.
Seems like i will have to abandon the character after all.

You may not have to abandon your character. I tried a scenario that you described on my fallout3 nv and the way i fixed it was by
using the console command "setstage 00154233 30" (no quotes). I hope that helps.

Wow, thank you so much, it worked.
Now i've finally finished my first character. Thanks again for all the help

A feel good story amongst much horror.

Well to us we have another trouble it always crach when the quest starts after talking to yesman and choosing tho start the quest we are teleported to the Hoover Dam and BANG CRASH... every time. We aren't using any mod, game is steam patched. we have ligthed the char to only have 1 gun armor and some ammunitions... everything else is left in the penthouse locker. timescale is well set to 30... but it still crashes. Any Idea??? Even if we take an older save it always lead to game crashin, we see the barrage and before being able to move it crashes.