Was the C: drive the boot drive?
If so there's your problem, you can't have the OS installed on a Dynamic Volume unless you attach an MBR directly onto that volume.
You also should have received a message when converting that C: drive if it was the boot drive, that this operation is not possible or could cause irreparable damage to your data if you covert it to Dynamic.
All I can y is you can try to convert it back to a Basic Volume by using a 3rd party partitioning or drive mgmt tool, and hope that this wll make it accessible again.
This may also help
http://support.microsoft.com/default.aspx?scid=kb;en-us;283421