Stop in for a cup of coffee

360DartGT66 said
I did that until I accapted that it didn't help any longer.

It could be a cable or something rubbing on a fan. I just installed a new graphics card (my son upgraded and I got his for cheap).

it doesn't take much to get something vibrating inside those things - next time it is off, open it up and check all the screws - main (mother) board and all