|"i've seen this but this is sadly not for the right version..."|
The Dell spec sheet in response #2 covers 6 different versions of the OptiPlex 486:
486/SL, 486/LE, 486/L, 486/M, 486/ME, 486/MXE.
They are also know by their processor speed. Yours has a 66MHz CPU & is known as 466/LE. If it had a 50MHz CPU, it would be 450LE; if it had a 33MHz CPU, it would be 433LE. Look again at the PDF in response #2, go to page 2, then look at the list of System boards.
message edited by riider