Please help can't use my computer because of something I switched

[Gabrysch]

So basically when I was trying to do dual monitors I was attempting to use a VGA cable. I wasn't paying attention and made the second screen my primary display, but because my graphics card doesn't support VGA, the "primary screen" is switched to the the VGA input which I can't seen. This means that I can't see anything to undo the settings and the screen I normally use is just displaying a blank screen because I haven't logged in or something I'm not entirely sure. I can't see the primary display so I can't even log in let alone navigate through control panel to fix it

 

[thx1138v2]

I'm not sure this will correct the problem but try it.

Power the machine off.
Disconnect both displays.
Power the machine on and let it run until you think it's done all it can. This is just a guess since you won't be able to see anything.
Power the machine off and wait one minute.
Connect the one display you want to use.
Power the machine back on.

Hopefully, the machine will detect the one display and use it.