Hello there,
we have a DELL laptop which screen is defect (we can only see very dark letters).
This is not so important, because we connect a second screen on the back, and this is ok with winXP and PartedMagic (VESA).
But it dont come to the second screen with LinuxMint13 (we see the very dark letters from LinuxMint but not the green on the second screen) and the liveCD and automatic boot (the owner want to install... Mint13 on the HDD!).
So, my next try will be to boot from the LiveCD into vesa.
But how to?
Is there a boot code? "we want to see green on the second screen" ? ;-)
I am new to LinuxMint.
Later I will say to the owner he should use Xorg. But a start with vesa would be ok in my opinion.

Not knowing which model, have you tried doing a FN+F8 (which is standard shortcut on MOST Dells)when it boots up to tell the laptop to switch from onboard LCD to external?

Solved: there was an advice in the dmesg like "put force_second_device=1 as boot code" (dont have the laptop here so its why I cannot write the correct text; the second screen was recognized but for any reason was not switched on) and there is no issue anymore.