I have a Dell Precision 4500 working well no problems with it. Diagnostics all OK.

I have been trying to connect a dell 1410x projector to it without success using a VGA cable that I know is good.

I am computer literate and have tried everything and am now looking for suggestions from users that may have seen this problem before.  Graphics card driver updated. I have been in contact with Dell support but they say that they no longer sell projectors and no longer have expertise in this area.  HELP !!