MacBook not connecting to external screen properly

I have had a MacBook 13"3 white for about 4 years now and it is still gong strong. It does seem to have one slight tick that is rather annoying. I often use this with other screens so I can have 2 desktops and over the years have had it plugged into many different screens. Lately it sometimes seem to auto detect the wrong resolution. ( like it thinks it's a different screen than the one I'm trying to plug in). It won't even let me mannuly change it in the system prefs. After a few unplugs and plugs in it works but i was just wondering if there is a way to clear the computers memory of past screens or something.

Any help would be greatly appreciated.

Reset the System Management Controller (SMC). LINK

Reset the PRAM/NVRAM. LINK

Try the SMC reset first as that's what controls video output.

Thank you. That worked perfectly!,