Hi fkasmani,
I presume, from your message, that you want your C-drive to be 50GB not an extra D-drive that's 45GB.
In my experience, Windows is not very good with these things. Someone needs to show Microsoft the LVM
You probably want to do something like this:
- Make a copy of your virtual-disk (.vdi file) -- keep this safe so you can put it back in place if this all goes wrong.
- Create a new 50GB virtual-disk and assign it to your VM.
- Use a Linux LiveCD on your VM to cp/tar everything from the old disk to the new disk.
- Change the VM's BIOS/Settings to boot from the new disk.
If it works, you can delete the old disk from the VM's settings.
Just make sure you get that backup (Step 1), then if this procedure burns you, you can undo your changes and restore the virtual-disk!
Hope this helps.