Boot-Sector Brain Surgery

Hi all,
Haven't made a post in a long time and I'm surprised my account is still active.

Here's the verdict; my laptop came shipped with an OEM Windows Vista installation. I wanted to dual-boot it with Windows XP but needed XP on the C: partition (plus the issue with older version of windows should be installed before a new version is installed) forced me to re-format, install XP SP3, install all the drivers and bring me to what it is now.

My laptop is fully functioning with Windows XP. I have a Linux Ubuntu 8.04 CD, Windows Vista OEM dvd and windows xp sp3 cd at hand. I want to dual boot my system with either windows vista, linux, or both.

Please answer these two questions:

1.) If I create a new partition and install Vista on the new partition, is it possible to upgrade the Vista installation to Windows 7 WITHOUT DOING ANY HARM AT ALL TO THE XP PARTITION OR IT'S BOOT LOADER? So I will then have a dual boot system with Windows XP and 7 (and both OS's fully working)?

2.) If I install Linux in a new partition alongside my XP partition will it be possible to install vista on a third partition AFTER I have installed Linux? So the order in which the operating systems have been installed would be:
- 1. Windows XP installed first
- 2. Linux Ubuntu installed second
- 3. Windows Vista installed third

Any help will be very much appreciated (as long as it's from someone who knows what they are talking about).

Thanks