Hello EDEd Welcome to the Windows 7 Forums!
There is another solution for accessing Linux volumes in Windows that actually assigns a logical drive letter. The Fat 32 partition ubuntu is on was most likely converted to one of the VFat file systems like ext 2 or ext 3 as part of the ubunut installation there. I used this one on previous occasion for Dual boots with Linux.
How to Access Linux Ext2 & Ext3 Volumes (Drives) on Windows
Access Linux Ext2 & Ext3 Volumes Directly From Windows using Ext2 Installable File System for Windows
Most of the Geek users prefer to have dual boot system with Linux and Windows OS installed on the same hard drive. Since Linux requires different file-system type then windows the volume is normally Linux formatted. This Linux Formatted partition cannot be access directly from Windows.
There may be instances when you are working on Windows and need to access Linux drive for some files and switching from Windows to Linux is the only way but it could be time consuming. How about if we can directly access Linux Ext2 and Ext3 volumes from Windows, Don’t you think it will be great savior for us? Well then here is freeware Ext2 Installable File System for Windows (Ext2 IFS for windows).
This will mount the Linux volume as a logical drive and assign a drive letter. The other option for direct access to just about any Fat 16, 32, NTFS, or VFat volume is to boot from a ubuntu live cd which will browse each.