I currently have Ubuntu 11.10 32 bit and Windows 7 dual boot in separate partitions. I am trying to do a fresh install of Ubuntu 12.04 64 bit (mistakenly installed the 32 bit 11.10 a little while ago.. I need a 64 bit version to support AOSP build) OVER my the exisiting 11.10 partition. I have referenced How to Install fresh 12.04 install to a PC with dual booting Windows 7 & Ubuntu11.10?, as well as other posts on using the Live CD to do a fresh install. However, the problem I am experiencing is when I bring up the install screen, it says the following:

This computer has multiple operating systems on it.  What would you like to do.

(3 options)

• Install Ubuntu 12.04 alongside them
• Replace all with Ubuntu 12.04 (Warning, this will delete files across ALL operating systems)
• Something else (you can create or resize partitions yourself)

This is different from what is in other posts, as mine states that there are "multiple O.Ses" and doesnt individually allow me to replace the Ubuntu 11.10. I don't want to replace ALL O.S.es: I need to preserve Windows 7 and am only trying to replace the old Ubuntu 11.10 partition with the new 12.04 64 bit. I did have Ubuntu installed via Wubi (I believe it was 10.04) prior to putting 11.10 in a separate partition, but I have removed it via Add/Remove programs in Windows.

I was wondering how to go about doing this... Should I use the "Something else" option to bring up the partition manager, and just assign my existing 11.10 partition with root mount point + swap space. Will this do the same thing by overwriting with fresh 12.04 install??

I appreciate all your help.