Partitioning

I have a linux machine (old one). I installed linux in it. Hard disk is 3.1 GB. NOw i want to uninstall linux and load windows. But while using fdisk from A:\ drive to remove the partitions it showed 3o4oMB Non Dos partition and 51MB Non dos partionwith 51 MB drive as active. And no logical dos drives. But when i tried to delete the ext dos partition it says “cannot delete ext dos when logical dos drives are present” but there are no logical dos drives present.

Now i cannot do anything neither load linux nor install windows .
Please help. Thanks in advance.