I upgraded to Windows 10 an encountered a problem with my TV's resolution (plugged in as a HDMI monitor): though I could still "set" a custom resolution in NVidia's Control Panel, it would keep the Windows 10 resolution, even after restarting and such, with fully upgraded drivers.
I fixed it by following the advice from here, which says:
Go to the Display Properties > Settings > Advanced > Adapter and check for an option that says something like 'List all modes'.
Basically, go into (Windows) Control Panel, to change the resolution, select the monitor/TV you want to change, click "Advanced Settings" (in Windows 10 and I think Windows 8 too at least), go to the Adapter tab (first one), and click the "List All Modes" button. I scrolled all the way to the bottom of the list that pops up, and my custom resolution that was previously set in the NVidia Control Panel (but currently unused) was there. Select the resolution you want, click "OK", and then click "OK" or "Apply", and it will give you that resolution.
Update: sometimes this doesn't work... after my NVidia driver updated, the custom resolution reverted, and redoing it and restarting my computer didn't fix it - nor did the custom resolution show up in "List All Modes"! The solution to this problem was to simply unplug my TV and plug it back in, and when I went to Control Panel again the custom resolution finally showed up.
Wow, a VGA CRT? I didn't know people still used those :) BRB, let me get my sliderule, scythe and bow and arrow... :D
Actually, according to the user manual you linked us to, it is supposedly capable of 1600 x 1200 @ 75 Hz. See this page of the manual.
Maybe the reason why it isn't scaling to the whole screen is that you're setting it to the lower resolution 1280 x 1024. Does your screen resolution properties show an option for 1600 x 1200 @ 75 Hz?
If it doesn't, you may have to download a driver for it. You can try the 32-bit Windows XP driver available for download from CNet (so I'm assuming the file is clean because it's hosted there, but YMMV). As far as I know, Windows monitor "drivers" for VGA monitors are just .inf files that tell the system about the supported resolutions... So hopefully this is all you need, and it should work even on a Windows 7 machine.
Best Answer
Presumably you mean the image does not cover the entire display surface. Actually this is typical for CRT computer monitors: there is no overscan like on CRT televisions. There may be some on-screen size & geometry adjustments, but some unused screen area is better than overscan.
A resolution of 1280x1024 does not conform to a 4:3 aspect ratio. The proper resolutions for 4:3 would be either 1365x1024 or 1280x960. I've found that the VESA timings for resolutions higher than 1024x768 are conservative and have large front & back porches for horizontal synch. The default timings generated by the video adapter result in squarish images when using a CRT front projector at 1280x960. To stretch the image horizontally I've used the custom resolution feature in the NVIDIA Control Panel to reduce the porch times/sizes. The front porch can be reduced from 96 pixels to 48, and the total (horizontal) pixels from 1800 to 1640 (which affects the back porch).
Powerstrip is another utility that can adjust the timings. However caution must be exercised when using these programs, as GPU and display manufacturers warn that improper timings can damage the display unit.