Multi boot default (XP, Vista, 7, Ubuntu)

I was originally running just XP Pro (and still use as my main OS) on C:. Installed Vista (didn't activate it yet and it's past 30 days) on Drive G:. Installed Ubuntu on D:. Installed Windows 7 RC1 son S: (in that order). When I start my puter, Windows 7 is the Default OS. I can't change the default OS to XP in Windows 7 (it only gives me the option for Vista). When I start in XP it shows Windows 7 (7 and xp only options) as default and when I try to select XP as default it jumps right back to 7. I'm thinking I may have to activate my Vista and do it thru Vista... [all OS run perfectly no issues at all] Thoughts? Ideas? Trying to save time... Thanx!

I think the issue is that the upgrade path to Win 7 is Vista, then Win 7.

There is no upgrade path from XP to Win 7.

Does your system support f8 at boot to give you a bios boot manager. Not the f8
for windows boot options screen.

My Asus board uses f8, other boards may use a different key.

If your board supports an f8 you may be able to boot xp that way

You may also be able to edit boot ini file

Here's a link for editing boot.ini http://support.microsoft.com/kb/289022

See this thread Triple boot XP, Vista, and Windows 7...

Easy method is to download and install this program, EasyBCD and you can change the default OS and even choose XP. And it's also pretty neat because it allows you to change the names of the OS's on the Boot Manager.