EASY!!! use the ‘DiskPart’ tool on the XP command line.
Use ‘list disk’ to find the volume number of the GPT volume, then use ’select’ to choose it
then use the ‘clean’ function and then exit the tool
You also can use ‘create partition’ command to create a new partition.
Updates: Worked on Windows 8.1 & 10 but not tested on Windows 11 yet