Cannot choose OS on startup

[imasterchris]

Hey there. I just installed Ubuntu 11.04 amd64 on my computer alongside my Windows XP partition. However, on startup, my monitor displays "Video Mode Not Supported" which I assume is the Grub2 interface to choose my OS. Unfortunately, it keeps booting into Ubuntu, and I cannot change it. So, through the command line, I made the default OS on startup windows xp. But now I don't know know how to change back... Is there anyway I can change the display settings to be supported by my monitor (it's native resolution is 1440x900)

Any help would be appreciated, Been using macs all my life, so I am a noob when it comes to Linux and Windows. Thanks in advanced

[atreyu]

I've never used Grub2 before, but w/regular grub, you can look in the config file /etc/grub.conf (or /boot/grub/grub.conf) to make changes.

Here's a simplified example of a grub.conf file:

default=1
timeout=5

title Linux
  root (hd0,0)
  kernel /boot/vmlinuz-2.6.30 ro root=/dev/sda1 vga=0x318
  initrd /boot/initrd-2.6.30.img

title Windows
  root (hd0,1)
  savedefault
  makeactive
  chainloader +1

The default of 1 means to make the 2nd kernel entry (0 is first, 1 is second, etc.) the default kernel, or in this case, Windows. The kernel entries all start a new line with "title" followed by some unique string.

The timeout value should be some number like 5 or bigger, to give you time to interact with the bootloader and select which kernel/OS you want, instead of it jumping right into the default kernel/OS.

The vga=0x318 is what might be giving you the "Bad mode" error. Just take that bit out. or better yet, make a new (third, in this case) kernel entry by copying everything from "title Linux" to the "initrd" line, remove the vga= bit and give it a different title (e.g., title Linux novga), b/c the title must be unique for each entry.

Then save and reboot.

Again, this is for grub - no idea if Grub2 is very different or what.