I apologize if I am posting this in the wrong area - I am brand new to Ubuntu, Linux and this forum.
I have been booting from a USB onto a Dell laptop without any issues - it seems to be rock solid and I have successfully booted into it many times. The problem occurs when I try to boot from USB on my Dell XPS. I am able to get as far as the main menu, where it asks you whether you'd like to boot or install from USB. When I attempt to boot from usb, I get a black screen for about 10 seconds, and then my PC starts its regular boot cycle all over. I don't even have an opportunity to do anything.
The only thing I could find that might be causing the issue is the the fact that the XPS has dual ATI Radeon HD 4800's. What really confuses me is that I was able to boot Ubuntu 12.10 from a USB on this PC before and battled the wacky video behavior, but at least I was able to get in and attempt to remedy the problem (not that I have any idea what I am doing).
All that I have tried was so far has been downloading the video drivers to the USB from the Dell laptop, but it always gets hung up when it has to build packages(?). I'm not even sure if that would work, but I really don't know what else to try.
Any help would be greatly appreciated!