which drives data will be erased when installed with system image

I have it and then I don't have it! It was on and now it's not having just finished up another clean install of 7 here.

I'm a little confused between and have not.

A post of diskmangement display of present system would answer whether you do or do not have a 100 MB System Partition.

I did have before nuking the first drive and creating as well as formatting a new primaty using GParted not the drive tools on the 7 dvd. This mainly to eliminate the additional drive letter since the 100mb had been initialized for viewing some time back to show just what files and folders were placed there.

The total was some 34.7mb out of the 100mb of drive space taken up. The second OS drive is where the 100mb is presently seen from restoring a recent system image in order to pick and choose which programs as well as files would be going to the fresh install. "Trimming the Fat" so to speak!

Actually, between your win 7 dvd or Win 7 System Repair Disc and the DISKPART command you could have carried out everything, although the end result is what counts. Some prefer to use Partition Wizard which does make some partition operations much, much easier. Thank god, for Partition Wizard because I'd hate to need to explain to someone how to shrink and merge partitions which disk management doesn't think can be shrunk, merged or moved.

You could use DiskPart to expand or shrink partitions as well. But trying to get those numbers correct can be a little "awkward" at times! Want to split a raw drive up into multiple partitions?

I think we both most will automatically prefer the gui method for any of that. The whole point of the 100mb was to show just how the drive tools during a normal 7 install not the command line option found in the repair tools would automatically create the 100mb on a raw drive. The advanced user on the other hand would simply choose to have or not to have this present following a clean install.

The idea of the separate partition idea of course was a security measure to prevent rootkit type malwares from getting in the way. Being generally hidden from view and inaccessible it wasn't prone to any virus or malware was the apparent MS thinking there.

I've never had any problem restoring a system image created by the backup feature in 7 or when using Acronis TI with or without the 100mb being there. Having just restored an image to the second drive here I noticed the 100mb was 101mb. Apparently Acronis used for that made room on it's own.