windows 7 - How to identify the purpose of a partition?

In the process of helping a friend with a task, we have run into a little snag.

They are using Windows 7 SP1, which came pre-installed by the system's manufacturer. They have never had any other operating systems installed on their computer.

According to Windows 7's Disk Management, their hard drive has 3 partitions:

1. 
   

   The first is about 2GB and is listed as "Active, Recovery Partition". That makes sense, as it's likely the recovery partition from the system's manufacturer. No file system is listed for that partition.

   
   


2. 
   

   The next partition is about 10GB and is listed just as "Primary Partition". No file system is listed for that partition.

   
   


3. 
   

   The final partition is listed as "Boot, Page File, Crash Dump, Primary Partition". The file system is listed as NTFS. This is obviously their Windows 7 partition.

   
   

How does one figure out what is the purpose of that 10GB partition?