I inherited a sever from another admin that built it with a very small system partition; C drive 10GB, Drive (Data) 70 GB.

What would you guys do to resize this partiton without flatten the server and starting over?
Have anyone used any third party application to resized your servers hard drive and was happy with the results?

Any advise would be greatly appreciated, the current C drive has about 300MB free..... I really don't want to flatten this thing and rebuild it if I don't have to.