Windows – Dual monitor with ATI radeon 4350

I had a similar problem with my 1680 x 1050 monitor.

I found that I had to use the "Desktops and Displays" section of the ATI Catalyst Control Center software and click on the "Detect Displays" button. Thereafter, it showed the 1680 x 1050 resolution as an option under "Desktop Properties".

You cannot use three monitors at the same time with that card (and every other card I know of with an HDMI port). The HDMI port uses the same circuitry as one of the DVI ports. Two monitors at once is the most you can do with that card, one DVI connection and one HDMI connection or two DVI connections.