virtualbox.org

The tutorial says it isn't possible but I know there must be a way. I tried making an .img of my 25GB partition and doing a chkdsk in Vbox but this didn't help much, it was still unbootable and no valid partition tables etc. My 25GB partition is on my 2TB disk and I cant copy the entire disk, so it would be good if I could just copy the partition. :/

some cloning applications, when run within a virtual machine, can make this occur.
The "physical source" needs to be mounted within the guest.
Expect the 'clone' not to be bootable - the virtual hardware is not the physical hardware of the "physical source".
Converters, such as Disk2vhd http://technet.microsoft.com/en-us/sysi ... 56415.aspx, do the necessary physical-to-virtual.

Not possible to answer without knowing the precise guest OS. Please choose an appropriate forum before asking questions of this nature. Or say what the guest OS is, and I'll move this topic to a better place.