det gør du her
http://www.its05.de/html/festplattentools.html sådan her bruger du den
Configures fixed disk partitions.
GDISK disk /CRE {/PRI|/EXT|/LOG} [/SZ:mbytes] [/FOR [/Q] [/V[:LABEL]]] [/-32]
[/-CE] [/X] [/Y]
GDISK disk /DEL {/PRI[:nth]|/EXT[:nth]|/LOG:nth|/P:partn-no|/ALL} [/X] [/Y]
GDISK disk [/STATUS] [/RAW|/LBA] [/X] [/Y]
GDISK disk /ACT /P:partn-no [/X] [/Y]
GDISK disk /[-]HIDE /P:partn-no [/X] [/Y]
GDISK disk /MBR [/X] [/Y]
GDISK /? [/CRE|/DEL|/STATUS|/ACT|/[-]HIDE|/MBR]
gdisk 1 /mbr
gdisk 1 /cre /pri /sz:4000 /for
gdisk 1 /del /all