Inspiron 660 MT , GeForce GTX 950, S2340L, no HDMI signal

Hello All - I'm having issues with my Dell S2340L monitor, that came with my Dell Inspiron 660 MT system.  I recently had to replace the original PSU, so I upgraded and now using a Corsair CX500 500W 80 Plus Bronze PSU - Works great and quiet.  I also upgraded the preinstalled 8GB's of Samsung MeM, to 16GB's of G.Skill Aegis F3-1600C11D-16GIS - I had on hand and the Intel 3.0GHz Ive Bridge CPU and Dell 084J0R (CPU 1) MoBo recognizes it.  My Dell Inspiron 660 MT came with Win 7, but a few years ago received the upgrade to Win 10.  Dell SupportAssist and Dell Detect Drivers, shows I have everything and don't need updates.   

But the issue I am having is when I install the GPU, it's an EVGA GeForce GTX 950 02G-P4-2951-KR 2GB single fan.  I keep getting "No HDMI Cable - The display will go into Power Save Mod in 5 minutes" or "The current input timing is not supported by the monitor display. Please change your input timing to 1920x1080@60GHz or any other monitor listed timing as per the monitor specification".   So I have uninstalled the EVGA GTX950 GPU, and have never been able install the software for it because of this issue.

I now have installed a Galaxy 9500 GT and it's software without any issues or these messages.

Please help and Thanks for your time.