LCD blank?
with Melzi powered up, restart PC
check in the system- hardware- devices- fi the COM port and USB serial are all okay
if you see them, them try to connect to the printer
if connects, then it is the LCD issue
by having Melzi board, you probably have a Zonestar P 802, if yes, then check the LCD holder.
un-mount the LCD from the frame and take off the back holder, you should see a pot there
try VERY carefully and gently turn counter clock wise to see if any changes, and then clock wise (never start to clock wise)
basically the LCD might be installed without one of the corner support screw and when installing it onto the frame the pressure builds up and compressed the POT and causing LCD to faint or to be too bright...
But if you can not connect, them it might be the Atmel chip that is out of service.....
good luck, and keep us posted!
cheers