[Pass]

Are they on the same physical drive?

You SHOULD be able to simply format the ext3 and swap partitions to NTFS (thus blasting the data) and then simply run a FixMBR in recovery console mode. That will overwrite the bootrecord removing the Grub pointer.

If they are on the same physical drive this will leave you with 2 separate spaces... If you are wanting one contiguous partition for Winblows then you will have to reinstall.

Now, as for how to remove the linux partitions... Since I'm assuming that you will be in Winblows doing this, you will need a program like Partition Magic or other partitioning program that will allow you to see the ext partitions -- since Winblows will not detect them.

Of course, the most simplistic way to do all of this for your average user is to simply back up your stuff and reinstall 7 from a clean slate.