You can delete it using Diskpart command line - you may need to specify overrride if it is a non standard partition type.
Better check in Disk Management and see if it is marked Active first.
Then you would have Unallocated space.
If it on the left ( in Disk Management view) you will need a 3rd party tool to merge with the 7 partition.
If you are certain you don't want it - easiest to delete it before installing 7.
In any case - here is a very good free partitioning app.
Free Download Partition Wizard
Please post a screenshot of Disk Management window.
http://www.sevenforums.com/tutorials...en-forums.html