I recently installed DSL (Damn Small Linux) onto an old 486 with 8mb RAM and a 1.2gb harddrive. After a lot of messing about I was able to get it to boot and start the OS successfully but shock horror! The mouse nor' the keyboard will work at all...
The keyboard and the mouse aren't broken as I used them on Win98 which ran on that machine before.
The keyboard has a 5-Pin Din connection, which I believe is could be the problem, the mouse is a serial mouse also, it is a very old machine. Is there any way I could make the mouse and kb work?

There is probably a faulty setting in X-configuration, /etc/X11/xorg.conf or XF86config
Wrong settings for mouse or keyboard might kill both.
So take a look in that file, post it here if you don't fix it!

And that means? How can I fix this?

Boot up in text-mode, adding 'single' or 'init=3" at boot-prompt. (Do you use lilo or grub?)
I don't know what text-editors you have, 'vi' at least I guess.
# vi /etc/X11/xorg.conf

Or simply post that file here if you don't know what to change.

I'm having a similar problem, but the keyboard works. I'm running DSL 1.2 on a P MMX at 166, with 32 mb ram. I am using the same connections, and the keyboard works (standard ps/2 connection with adapter), but the mouse doesn't (ps/2 to serial adapter). The mouse is working fine (tested on win95/98), but wont configure/work on dsl. Should I try an actual serial mouse before doing anything complicated (would a different mouse affect it at all)?