So kinda nervous from devolving a short from to much paste.

I went way overboard with the thermal past on the cpu last time, I took apart an old computer and it had thermal paste everywhere so I figured no big deal to use a little extra. I’ve since learned some paste are more conductive, I’ve tried to get it off my fan as much as possible. ISO on a toothbrush type situation. So every time I jumped the mobo, cpu fan would spin for a sec and stop, no post, no nothing. I got a new board, going to have another go at it but i’m building it out of the case, just on a rubber mat, there is nothing to stop that from working right, I dont need any screws in the board right? What else can I do to make sure the 8 pin dont short? Thanks for your time, cheers.