Display on handset does not display any info!

The display could be bad or the didplay driver could be bad or it could be a simple wiring problem if you're lucky. Try pressing around the edges of the display to see if anything appears (press firmly but not so hard as to break anything). If you are mechanically inclined, open up the handset and connect the battery so the handset works. Normally the display is connected to the phone circuit board by a ribbon cable and frequently there is a tiny "edge card connector". If present, make sure the connector is plugged in completely. Watching the display, try pressing on the ribbon cable where it attaches to the display and to the circuit board. If anything appears, keep trying to isolate the problem.

I recently had this same problem with a Sony handset but I was not able to find anything as I just described and I ended up replacing the handset with a new one of the same model. Good places to look for a replacement are eBay and Amazon.