Upgrade Vista 32 to 64 bit while keeping user data AND explain install options

I fix PCs for a living. This is for my customer who has purchsed a newegg.com Vista Home Premium 64 bit OEM Full Install DVD. Note: Newegg OEM Vista DVDs can be used on ANY HW. Customer currently has 32 bit Vista Home Premium on a custom built PC with EVGA mobo and EVGA graphics card. He wants me to upgrade it to Vista 64 bit for reasons that do not matter here.

There are two RELATED questions here

(1) Most people say that to upgrade Vista 32 bit to Vista 64 bit you must reformat the HD wiping out everything so all user date must be backed up FIRST. However I found the following post in a forum at
www.eggheadcafe.com/conversation.aspx?messageid=33971744&threadid=33971699

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Can I upgrade Vista 32 to Vista 64-bit? - Ian D  
07-Feb-09 08:36:12
 
It has to be a clean install, but if you install retail upgrade
64 bit Vista in the same partition as 32 bit, it will preserve
your 32 bit Vista in a windows.old folder, provided you
don't reformat.  The value of that is, if 64 bit doesn't work
out, you can revert to the 32 bit version.  Also, files in
non-OS related folders in that partition will not be touched
by the 64 bit installation.
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The only part that interests me IS THE LAST SENTENCE. The "non-OS related folders" means THE USER FOLDER THAT HAS ALL THE USER DATA SO THAT POST IMPLIES THAT I DO **NOT** HAVE TO REFORMAT THE HD and back up and restore the user data. Also the Program Files folder where Quicken usually stores the Quicken DB. And also C: where some people put user data.

Furthermore this makes sense to me because Win XP allows this by (as Ian D says to do for Vista) install XP from CD into the existing XP partition and do not reformat it and then choose Keep Current File System intact at the next window. SO IF XP ALLOWS IT, WHY NOT VISTA ??

Regarding Ian D referring to the "retail upgrade 64 bit Vista", I assume that the Newegg.com OEM Full Install DVD can do ANYTHING the Upgrade DVD can because that has been the case for XP Install CDs. This may or may not be true.

END OF (1)

(2) As a separate but related topic, the Vista Custom (Advanced) install has a Wijndow with a lot of choices (see below). I want to know what some of those choices are for and which ones to choose to keep the current user files.

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At www.petri.co.il/install_windows_vista.htm are Vista install instructions. I am focussing here on two screen shots there

(a) www.petri.co.il/images/inst_vista_rtm_6.gif

There Microsoft says that "this option does not keep your files ....".   It appears that Ian D. disagrees with that. Now granted we are not choosing the Upgrade install option but (see below) I do not think it matters. And with Win XP, one does NOT need to do an Upgrade install to keep all the user data if my instructions above are followed.

(b) www.petri.co.il/images/inst_vista_rtm_partition_1.gif

THIS IS THE INSTALL STEP THAT THIS ENTIRE QUESTION REVOLVES AROUND. NOTE ALL THE DIFFERENT OPTIONS ON THIS SCREEN.

Also note that IN MY CASE THE EXISTING HD PARTIION WILL BE DIFFERENT THAN SHOWN BECAUSE IT WILL HAVE VISTA 32 BIT IN IT VS A NEW HD THAT IS SHOWN.

QUESTION 1

If I want to do a clean install (i.e I already backed up the user data) MUST I FIRST REFORMAT THE HD ?  The instructions say to just click Next as shown at

www.petri.co.il/images/inst_vista_rtm_partition_2.gif

and clicking Next will Reformat and then install Vista 64 bit (per the text instructions at the first link above) BUT I BELIEVE THAT IS BECAUSE A NEW HD IS ASSUMED WHICH IS NOT MY CASE,. i,e for my case MUST I FIRST CLICK "FORMAT (assuming that I have already backed up all user data)? And only after Formating do I then click Next ?

QUESTION 2

Per Ian D.'s forum post at the start of this Question, is there a way to NOT REFORMAT AND KEEP THE USER DATA assuming the existing partion has Windows 32 bit in it.

Example. Just Click Next. Will  that work ?
OR
Select Extend>Apply and then Click Next? Will that work ?
OR
YOU TELL ME THE OPTIONS TO CHOOSE HERE
OR
You disagree and say there is NO WAY to keep the user data.

QUESTION 3

(z) Are ALL the options shown used by hiliting it (ex Delete) AND THEN CLICKING APPLY?? I.E Until you click the Apply button, Delete or Format or Extend or whatever does not happen ? IS THAT CORRECT ?
(a) What is the Load Driver choice for ?? For Loading a RAID drive ??
(b) What is the Extend choice for ???
(c) What does the "Asterick New" text ( *New) at the right mean? Is this displayed because this is a new unformatted HD and I will not see that in my case ?
(d) What is the Refresh chocie for? ie,. When will choosing Refresh lead to a different display then before choosing Refresh?

Regards,
   Mike