I've seen exactly the same kind of stripes when using a few other things that put my Inspiron 8200 into 640x480 resolution (a couple of DOS-based disk-repair utilities do this, among others) so I suspect it's actually a Dell BIOS bug.
To work around it for Ubuntu, I added vga=792 to the "kernel" lines in /boot/grub/menu.lst to put the display into 1024x768 24-bit color mode during boot. This also gives me very nice 128x48 text on all six text- mode virtual consoles once Ubuntu is up. -- boot splash has dashed vertical lines on inspiron 8200 https://launchpad.net/bugs/26899 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
