Samsung Syncmaster B2030 - no option to set resolution to 1600 x 900

This should be quite an easy one to fix. At some point Windows has installed the driver for the larger B2230 monitor. The error could have been a mistype in Windows own native drivers when the OS was initially installed. The incorrect driver is probably still installed but not displayed as Windows now correctly identified your monitor as the B2030.
So I think you have a 'Ghost' driver in the Device Manager unders Monitors. This won't be displayed unless you turn on non present devices.

Right Click My Computer, then Properties. Click Advanced Systems Settings then Envoironmentsl Variables. We'll add 2 new variables to System Variables. Click New... and add 'devmgr_show_nonpresent_devices' to Variable name and '1' to Variable value then OK, plus add 'devmgr_show_details' to Variable name and '1' to variable value.' Don't include thew quotes. Now Reboot. Open Device Manager, click View then Show hidden devices. Click Monitors and it will show all monitors that Windows thinks has been attached, past and present. If the Monitor B2230 shows up, Right Click and Uninstall. Tick uninstall drivers if that box is there. Repeat for any other Ghost Monitor drivers, if there are any. Reboot. Now the only Monitor drivers Windows will have installed is the B2030 with a Max res of 1600x900.

sorry, I missed the link. Bugger. That's what it usually is.

If it's doing excactly the same thing in a different PC, I would be looking at the cable, possibly not firmly connected or damaged. Is should be just a straight VGA to VGA cable. No adaptors or anything. Your Dell just came with the onboard Inte HD graphics. Just checking that you didn't get a model with the optional AMD Radeon 63/6400 series.

I've re-read everything. It may be an incorrect EDID on the monitor itself. Windows installed the incorrect (B2230) driver, then you manually installed the correct one (B2030). That's where the issue is.

also, are you definatelly sure you don't have the larger 22inch B2230

Anyway, try Checking VGA Cable, then open Device Manager, Monitor, Right Click SyncMaster B2030, Properties, Roll Back Driver. Keep Rolling back until it's greyed out. You should now be at the first Monitor Driver that Windows Cached. Uninstall that Monitor Driver and tick with Drivers, Click Scan For Hardware Changes (it's the Icon under Help), It should install a Windows generic monitor driver. Update that driver with the SyncMaster B2030 driver from Samsung. If there is no drivers to roll back, just skip that stage and go to Uninstall Monitor driver with tick in Drivers. Scan for Hardware changes. Repeat until no more monitor drivers. Update to B2030 driver.

If all that doesn't work, I would download a program called MonInfo. That will show you what EDID info your monitor is sending. See if it's got the correct name.

this is quite informative on setting up monitors using eyefinity..
Shot Gaming - Gaming Under the Influence

- it might help.. (??)