Sounds to me like you have corrupt CD images. Has happened to me before. You should verify the checksums with something like this tool: http://www.irnis.net/free.shtml
Also, grab the latest Knoppix or MandrakeMove. These will let you check hardware compatibility before you commit to a full install.
And finally, it is hard to help you unless you give full specs of the machine, though in this case I'm not sure it would tell us that much - RAM is just RAM after all.
HTH - TIM