First I need to putty over to my ESX host and expand the disk here using the vmkfstools utility:
I picked a test machine called VCBTest to perform this procedure on.
The disk expansion takes place immediately:
Once the disk is resized, I need to use a 3rd party utility called gparted to resize the boot partition in Windows. I downloaded gparted from http://gparted.sourceforge.net/download.php
and copied it to my Data Store. I then configured the VCBTest vm to boot from that gparted iso:
gparted iso is based on a Linux distro:
Once gparted boots , I can modify the size of the partition:
After the resize is done, I boot up that vm and when it comes up, the boot drive is properly re-sized to 12 Gb: