You may be able to create a new VM and restore the OS partition to the VM's virtual disk. Depending on the guest OS and the drivers needed for the virtual disk controller, you may need to inject the appropriate drivers after restoring. For Windows guests this may work using the VMware Converter's "Configure Machine" option.
please rephrase your question
vmdks are images that boot from harddisk
isos are images that boot from CD
both formats are very different - so we need to know what you want to do in the first place