help no internal but i want to boot with external

[kylejjjjj]

ok i have a laptop that just recently had a hard drive fail so i removed it i have an160 gig external that i want to install Linux on so i got the live cd version of Ubuntu started it up pluged the external drive in whent through the install and set it to boot first but when it boots i get this

it says missing modules cat?/proc/modules;is/dev
and so on what did i do wrong

[kylejjjjj]

ok umm i think i got it on that screen i typed help found the command exit and it booted up so is that normal or am i still doing something wrong