wait a sec.
you want to ENABLE them, right? Unlocking is something different.
anyways, a stock xbox HD does not have a G partition that you can enable. Only a few have a small F partition. This can be accessed by formating the F drive and enabling it in the dashboard. C partition is already enabled, but don't tuch that one. As you are running a softmod, that's where your Vital files are stored. Another vital folder is E:\dashboard\. Do not delete/rename that either. To use a G partition you have to get a bigger harddrive (bigger than 137Gb) and put it into your xbox.