Help Please - Partition Problem :(

Attached is the screeny of how my drives are partitioned - this was all done before I received my comp from a family friend who helped me build it. All I wanted to do was simply shrink my H: (originally 200gig) and reallocate it to my F:. So I followed the online tutorial on how to use Vistas inbuilt partitioning program and easily managed to shrink H: down to 100g. Now I have the other 100g unallocated as shown.

My problem:

When I try to extend H: or even when I try to create a new simple volume with the unallocated space, it takes me through the wizard but when it's time to 'finish' I get this -

"The operation you selected will convert the selected basic disk(s) to dynamic disk(s). If you convert the disk(s) to dynamic, you will not be able to start installed operating systems from any volume on the disk(s) (except the current boot volume). Are you sure you want to continue?"

Whether I click 'Ok' or 'Cancel' I get the same result which is nothing! Please help! What do I do? I have unusable 100 gigs of storage sitting there

Try right clicking on the black bar of the unallocated space and select extended partition. Once created, repeat the procedure and create a logical partition from the extended partition. Worth a shot anyway.