I sincerely hope you mis-typed and actually meant a 240G partition for /, as the minimum size is about 20 G for system files.
If you really set the partition sizes too small, that is likely why the system froze. Go back and set partition sizes more reasonably over the minimum system requirement and it probably will allow you to continue.
LMDE Mate 64-bit, LM17.3 Cinnamon 64-bit
Debian Mate 64-bit, Xubuntu xenial 64-bit, Ubuntu-Mate 14.04 64-bit, Antergos Xfce 64-bit, PCLinuxOS Mate 64-bit