Struggled with this for several hours. What's missing from all the other answers is - how to login to remove drivers...
So here it is:
If you do a PC to fusion migration, and when the windows VM comes up, the "send alt-control-del" doesn't work, you need to remove the touchpad driver (from control panel, uninstall programs). One way to do it is from the original PC, and then migrate again. In my case, I was a little too liberal in driver un-install and completely killed my windows (BSOD seconds after boot). Lucky - I still had the locked VM. so first thing I did was clone it before I kill it too.
then I found out the NAT address of it:
cat /var/db/vmware/vmnet-dhcpd-vmnet8.leases
Next, launch remote desktop and connect to the running locked VM. It will let you login.
uninstall the touchpad driver.
restart the VM from the fusion menu.
keyboard will now respond and will let you login to your migrated windows.