I know I need to do a clean install to replace 32bitvista w/ win7pro64.OEM Must I reformat hd or just assure a boot from cd with OEM disk in place? I know I need to maintain old files until up and running just in case things don't go as planned. Surprise, surprise!
A clean install means none of your (previous) files will remain.
Boot from OS DVD; when it asks you where to put Windows, you can point it anywhere you like.
You can point it at a new harddisk - thereby giving you a new multi-boot menu offering Vista or Win7.
To replace the Vista, tell it to delete the previous OS partition.
Sometimes you'll find many small partitions. I bust 'em all out until the harddisk's blank (just like factory-new). Big HDs are 'in' these days, heheh...
Today we have C: D: and E: hardisks - these used to be partitions on a single drive, just a few short years ago!
Or by all means, keep a partition that has all your precious files on it.
Harddisks are cheap. You can run two or even three of them (which can actually speed up your computer).
Anyway, if you tell Windows to go to the big empty space it will then swing into action, both partitioning and quick-formatting the space automatically with no further input from you.
If you DO want smaller partitions or whatever, you can do that too, under the 'advanced' tab.
Best way to do this is to make a back-up of your files to an external drive for example or burn them on DVDs. It's not a good idea to install Windows on the same partition as a previous Windows installation without formatting otherwise things could get messy.
I strongly suggest you format the drive and start with a clean installation (for me the definition of a "clean installation" means formatting before). By the way, at the beginning of the Windows installation it allows you to manage partitions and format.