Simon, This site is often useful for linux on archaic laptop hardware However I only found two Umax entries (neither the same as your beast) and people were using Mandrake...

The Mint install experience sounds similar to mine (on a saintsong espresso pc) where I got a blank display and then on/off access of CD. That put me off Mint :-( There might be some hardware that installer doesn't know what to do with e.g. when creating X settings. AFAIR my beastie did install with other distros e.g.Fedora. If you can get another live distro (e.g. knoppix) to boot the umax then maybe you can scope out some hardware clues? However, this might be a long trek....

http://www.linux-on-laptops.com/umax.html Hope that this helps, Mark