Understood, there may not necessarily be another partition
What happened is that your friend made both installs...on the same partition. That's why the boot.ini file reflects 2 installs, but there is only 1 C: partition.
On that C: partition, there should be two Windows folders...one for XP Pro and one for XP Home.
Both Windows folders should be visible from either version of XP, because they are on the same partition. One may be labeled "Windows", with the other labeled "Windows.001", hard to say. Bottom line: If two Windows folders are on the C: partition, you have the situation I envision.
Take a look at the folders in Documents and Settings. The My Documents folders are part of this set of folders.
You could also just use the XP search function with a wildcard to search for files of a given type. When they show up in the search results, you can try to move them to wherever you want them.
XP FAQ, Two XP Installs On Same Partition - http://www.michaelstevenstech.com/xpfaq.html#20