|The native resolution for the E2260 is 1920x1080 @ 60Hz. Anything else is going to look "bad". The 600M is old (2003?), has outdated Radeon 9000 graphics, & doesn't have a widescreen display.|
Disconnect the splitter & run the monitor directly from the Dell. Assuming you can see the boot screen, start tapping the F8 key, then select "enable VGA mode". That will get you into Windows at 800x600. Then you can reset the resolution. I highly doubt you're going to get HD resolution with that old Radeon, but it may become an option if you update to the most recent available graphics drivers.