Win7 Upgrade - Multiple boot question....

[#1]

Hi all,
I currently have a 3 partition "System Drive", with my "primary" copy of Windows XP on partition 1 (C:), data on partition 2 (T:) and a secondary copy of Windows XP on the 3rd partition (E:), together with an installation of Ubuntu that was done under the Windows WUBI installer, with the actual WUBI virtual disks as folder on a 2nd hard drive (D:)....  Currently, upon boot, I get the standard Windows (XP) multiple boot option screen, with 3 boot options - primary XP, secondary XP and Ubuntu.
My understanding of my boot sequence at the moment is that after looking in the boot sector, the "boot.ini" file in the root of primary XP (C:) is then referenced so as to display my 3 boot options (Primary XP, Secondary XP, Ubuntu) - with a straight boot into either XP based on the relevent entry in "boot.ini", although for the WUBI installation, before booting from the "virtual disks", there is a dependancy on it needing to read/reference a "*.mbr" file that was placed in the root of C: during the WUBI install....
I am looking to do a *clean install* of Windows 7 Pro into the first partition (i.e. not touching data in the other 2 partitions), thus completely overwriting only my "primary XP" - and know that Windows 7 (actually from Vista onwards?) bootloader changes to using BCD, so wondered if anyone knew if, during a *clean install*, the Windows 7 installation routine will have "made note" of my current multiple boot scenario (including copying the boot.ini and *.mbr files from the current root of C:), and re-instate the multiple boot all after it's finished installing?
Or with a *clean-install*, will I just lose my current multiple boot set-up?  And if I do lose it, is there an easy way to re-instate at least the option to boot into what is currently my 2nd XP installation on partition 3 of my system-disk?  (Ubuntu was just a test, but would be handy not to have to re-install). E.g. if I do lose the multiple boot, if I keep (or recover from my pre-install backup) a copy of "boot.ini", and use something like EasyBCD to edit the Windows 7 boot, can I just re-instate the old boot.ini and it will at least give me the option to multiple boot, to either new Win7 or old seconary XP...?
Thanks,
P.

[#2]

I can't answer in relation to Ubuntu, but the only way I've ever got multiple boots to work with Vista or W7 is to install XP first.
Mind you, I don't think I've ever had more than 1 "alternative/old" system to boot to either.
(I currently have 3 such dual-boot systems - W7x64/XPpro, VistaBusiness/XPhome, VistaUltimate/XPpro)
On some systems I've got around such problems (in the past) by changing BIOS settings to boot from different drives.
The new boot mechanism is much more complex to manage than boot.ini (which I've meddled with many times) so I've never got into the details, maybe someone else has?

[#3]

I have a multi-boot system with Windows XP on disk1, Linux (Mandriva 2010.1) on disk2 and Windows 7 on disk3.  I use grub from the Linux installation to handle the boot process.  
My system differs from yours in that I have installed Linux into separate partitions on disk2 (/, swap and /home).  I also installed Windows 7 from within Windows XP thus leaving Windows XP in C: on disk 1 whilst installing Windows 7 in Q: on disk3.  
I originally installed Windows XP, then Linux and most recently Windows 7.  Using grub enabled me to easily rebuild the boot loader after the Windows 7 installation left me with the ability to boot into Windows XP and Windows 7 but not Linux.  I am not familiar with Ubuntu, but if it is anything like Mandriva there will be a Rescue System on the installation DVD that will enable the grub boot loader to be rebuilt if necessary.  However, given that you have modified boot.ini to take into account your Linux installation maybe you will be OK after installing Windows 7 (not sure on that one).  
The above may or may not be of immediate use to you but it may give you some alternatives to consider.
Screen shots attached.
Edit: minor modification to attached pdf

[#4]

Forget lilo or grub... XOSL is the ultimate in boot loaders. Win32 style GUI saves horrible config files and it will boot pretty much any OS off any drive though that doesn't include usb drives as far as i'm aware.

[#5]

All sorted - sort of....
I installed Win7 as a fresh install in the partition that had my primary XP (1st partition of "System Disk") - doing a format during install, so losing all boot information (e.g. a boot went straight into Windows 7 - no options). Afterwards, installed and ran EasyBCD under the new Win7, adding a new entry for a Windows XP boot, and letting it "find the XP installation automatically" - which it did, on the 3rd partition of my "System Disk". Rebooted, got the Windows 7 multi-boot menu, and was able to boot into (what was my) 2nd XP install -  now simply my alternative OS to Windows 7. Lost my Ubuntu boot, and guess I could try and get it back using EasyBCD again, and restoring the .mbr files from original XP root - but can't be bothered - will look at a fresh Ubuntu install (probably still WUBI, so as to avoid GRUB/etc. on a family PC that's primary a Windows workstation) some other time.
One issue I had to resolve - my initial XP installs were with the (ASUS P5B) motherboard SATA controllers set to IDE (emulation) in BIOS, and I wanted to go AHCI.... so set to AHCI for the clean Win7 install, which went o.k. But then after getting the multi boot sorted, booting into alt-XP caused a BSOD/reboot. Solved that one by changing BIOS back to IDE, (which still allowed the Win7 based OS/boot selection screen to appear.....??), and forcing an install of the Intel AHCI drivers onto the disk controllers in XP - at next reboot, changed BIOS back to AHCI and selected to boot into XP, and all worked fine (XP "found new hardware", and required restart, but o.k. working with AHCI after that).
So with a clean install of Windows 7 on a partition that once had XP working o.k., and having got both OS working on AHCI instead of IDE - a productive weekend's work. Just wish the paid employment always went so well.....
P.

[#6]

I have a 64 bit Ubuntu installed via WUBI into a 64 bit Windows 7 for about 6 months now.
It's very useful for rescue purposes and also for backing up the entire Windows 7 filespace.

[#7]

I could swear blind I left a reply here last night suggesting the use of VM's...

[#8]

You did - at 00:40; I stil have it - and my further reply/question that I posted at 06:58 this morning, onscreen on my other laptop!!! 
Weird thing is, looking back at that laptop screen, your reply was #3, mine #4 - which means that Fox's one wasn't there when you/I posted - but I swear that I'd read that reply sometime yesterday, so it must have aslo gone missing at some point (and has now re-appeared?).
Maintenance going on the forums, perhaps?
?

[#9]

My reply was sent shortly after I'd been unbanned for mentioning Plusnet and encryption in the same sentence.
Oh dear! I've done it again!

[#10]

Very odd! For a moment I thought I'd either imagined it or dreamt it!