router question

[Tom Daly]

Raymond:
It was me, Tom, and not Chris-from-Owen-Sound with the vanishing command 
line history issue ...

I burned a knoppix cd, yanked the feed from modem and ran rkhunter 
(command not found ...) and chkrootkit (wanted root, but that worked ok) 
  Report was a constant stream of nothing found, no problem anywhere.

I did find that it's "only" the root history that's gone ...

 >Unfortunately the only true way to be sure you aren't compromised
 > is to re-install, which is no fun, unless you like that kind of thing

I would not mind doing a re-install (never a bad thing to learn 
something), but have been searching in vain for a plain language 
tutorial on how to do so.  Any pointers (as in- to links) would be great