So I'm new at linux and don't know what I'm doing

[Justin]

I have a dell precision m90 laptop and a 250gb freeagent external hdd.  
I just reformatted and installed ubuntu 7.10 on the laptop.  I have all 
my files and what not stored on the external.  When running live from 
the disc, I could access the drive but now that it's installed, it says 
the drive is unmountable.  Would I be better off just waiting until the 
installfest and asking there(I want to set this up as a windows 
xp/ubuntu dual boot) or is there some little tick box that I'm not seeing?