im not also mentioning about formatting the hard disk in that post of mine that you quoted
you can't change the partition size your hard disks sa disk manager. ingnon lang nato na 40g ang imong hd, 20g ang imong drive c then ang d kay 20g. there, dili na gyud na nimo ma-change. bisag himuon pang 10g ang c then 30g ang d. pero if ingnon lang nato na ang c nimo kay 10g then naa kay 30g na unpartitioned(which never happens most of the time kay himuon man gyud ning partition), pwede nimo tunga-tungaon ug kapila ang imong 30g na unpartitioned.