The long of the story is: I purchased a laptop. I installed the Canon software and then had a few problems with that laptop. So... I returned it - - with the disk still in the laptop.
I didn't notice for a few weeks, and now the disk is gone forever.
Can anyone suggest what do I need to do to get another?

Thanks very much.

Contact Canon at Canon U.S.A (http://www.usa.canon.com) and navigate to the support page.

Not sure if these direct links will work but give them a try.
5DmII support:
Canon EOS 5D Mark II Digital SLR Camera (http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&tabact=SupportDetailTabAct&fcategoryid=226&modelid=17662)

5DmII brochures/manuals/updates:
Canon EOS 5D Mark II Digital SLR Camera (http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&tabact=DownloadDetailTabAct&fcategoryid=314&modelid=17662)

AFAIK, all the software cantained in the disk is available for download at canon's website.

AFAIK, all the software cantained in the disk is available for download at canon's website.Last time I looked I only found updates which means that you need the original disk. I am sure that some kind soul can copy it for you if it's too much hassle getting one direct from Canon.

I was away from my home base for a while. I had a mac and pc laptop with me. I left the Canon disk at home and only had the Canon software on the Mac.

Tried to download software for the PC. No can do. Only updates.

Called Canon. Explained my problem and asked them to me the software.
No can do. They suggested going to a Canon store or find a friend that would loan me a disk.

Unbelievable.

Let us know if you have a better experience.

The update software you can download from Canon's site does check if you have a previous version already installed, but (currently) it does this by simply checking if a registry key exists.

So if you create the registry key, then you can install the software you downloaded.

There are many pages describing the keys, e.g. this one: install Canon camera software without CD (http://www.northlight-images.co.uk/article_pages/install_canon_software.html).

Thanks very much everyone!

A community member here has offered to send me a copy of the disk (Thanks again!).
If I understand correctly, it doesn't matter what version he sends (though, since we're all 5DM2 folk, I figure it will be the latest disk) because I can Update the software once I have the software in my computer - and it's in my Registry.
Your's would have been my next choice, Thane, so thank you for that suggestion.

Thanks again for the help and suggestions!