Can't Boot From Disc

[laplacian13]

Hi All,

I have Mint 12 installed on my Thinkpad laptop and have installed many other distributions on it in the past with no problem (LMDE, ubuntu, openSUSE, etc). I just tried to install Lisa on my Dell XPS 610i desktop, but for some reason am having trouble. I put the Mint disc in my computer and restarted it. On my Thinkpad it auto-boots from the disc - this didn't happen on my desktop, but I pressed f12 to get to the boot menu and start from optical disc. The mint boot menu thing pops up as expected. When I press "Start Linux Mint", I see the standard text:

"Loading /casper/vmlinuz...................................................................................................
Loading/casper/initrd.lz..................................................................................
.......................................................................................................................................
.......................................................................................................................................
Ready."

And the screen flickers as if Mint were about to start. This is what usually happens, and is what happens on my Thinkpad laptop. However, instead of starting Mint, my computer goes back to the Dell splash screen and tries to start Windows! I've gone back to the boot menu and tried again, but the same thing happens.I've tried remaking the disc, using different dvds, and I even tried using the Mint 12 RC disc I used to install Mint 12 on my laptop (because I know that disc works) but the same thing happens. Any idea whats going on? Is there some sort of setting I need to turn on or something? Hopefully it's not a compatibility issue, I need to send my laptop in to get repaired and I need mint to do some programming on this computer in the meantime.

Thanks,

[laplacian13]

Edited the post with accurate output while starting the computer. Anybody know what's going on?