I have a little experience in partitioning and if theirs anything that ive learned its not to attempt it, It usually tend to cause problems. I was a bit confused by your post but if your looking to erase a partition download the latest ubuntu live disk (ubuntu.com) and boot up, use the G-parted tool to erase the partition you want and resize the partition you have to the max capacity of your HDD. I belive its possible to do this in Vista but I like using ubuntu instead.