Ubuntu :: Change The GRUB Bootup Menu's Default Choice?

Yesterday I installed on my laptop (an IBM Thinkpad T42) "virt manager" using the Synaptic Package Manager. I'm running Karmic.

As part of the installation, SPM had me reboot the computer (which is dual-booted with Windows XP, which I use less than 1% of the time). The new GRUB screen came up showing two new initial lines, the first 2 of the following 4 lines:Ubuntu,

Linux 2.6.31-19-generic-pae
Ubuntu, Linux 2.6.31-19-generic-pae (recovery mode)
Ubuntu, Linux 2.6.31-19-generic
Ubuntu, Linux 2.6.31-19-generic (recovery mode)

When I allow the default choice of the first line to prevail, Ubuntu boots up into a condition in which the Wireless Network Connection fails to open, and in which nothing I've been able to think of makes it open.

If, instead, I scroll down to the third line (which was the initial default choice line, i.e., the default choice line prior to the "virt manager" installation), Ubuntu boots up into a condition in which the Wireless Network Connection operates as usual, viz., immediately.

Scrolling down works, but it would be better, it seems to me, to return to the condition in which the current line 3 either becomes line 1 or else becomes the default bootup choice.

I've used SPM to uninstall "virt manager", but the 2 new intial lines in the GRUB options remain. I understand that with Karmic's version of GRUB, viz., GRUB-2, it is no longer possible to change the bootup menu choices easily.

how I can either eliminate the first 2 lines in my current GRUB screen, or make line 3 the default choice?