Linux tends to be happy with intel, nVidia and ATI graphics if you want the fancier drivers. Otherwise it'll work, but nothing fancy.
On the other hand, as suggested above, it may be the monitor that's not being properly recognised.
On a third hand - which version of Ubuntu are you using - some of the older versions have issiues with getting resolution correct.
I'm using the latest version of Linux Mint - it's based on Ubuntu, but with some improvements. It installed on me system with everything working correctly. Windows7 (RC) installed with 3 items needing extra drivers!!
Linux Mint click here I use the Gnome version - haven't looked at the KDE version.
Scroll down until you see Section "Device", it should be close to Section "Monitor and Section "Screen".
Now take a look at which driver Ubuntu has loaded for you.
You may find it's already correct.
To put it bluntly, the video chip you're trying to support is so far down the bottom of the pile, it will probably turn out, you're trying to get blood out of a stone.
By far a better bet, would be to take a visit to ebay, and find a very cheap Nvidia card (with a decent amount of RAM) if you've got a spare slot. Nvidia is still better than ATI in Linux, though the later is catching up.
I think I will tick this as resolved. This machine is an old Duron 900 with onboard graphics, I also have an old Pentium 111 750 with an AGP Nvidia card but no hard drive or ram, so I think I might transfer Hard drive and Ram and start over again and see how I get on with that one.
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