You CAN actually revert to a Basic disk from a Dynamic disk. The process is not for the faint-hearted, though.
Have a look
here and
here.
The way I see it, you would have to back up all your data anyway, so when you have done that give the above a go - what have you got to lose? The worst that happens is that you have to reformat the sisk and install from scratch.
A Dynamic disk is actually a partition spanning the entire disk, which is then subdivided into the logical volumes that can be combined to span multiple disks or create software RAID. This is why a partitioning tool won't work.
If you do a Google search for dynamic partition you can find more information than you ever wanted!
Good luck!
SD