cannot remove partition using disk utilities

Aloha from Hawaii, I hope everyone is having a good day. The problem is with a mbp running Snow Leopard. I created a dual boot with win 7. I was playing around with the partitions, and at one point installed SL on both partitions, sure i did some other bone head moves that i can't remember. Now cannot remove the second partition. I think i may need a boot disk with a application to partition the HD from the disk? Thanks in advance for your help.