Static electricity While answering my DCT646 cordless phone, a noticeable discharge of static electricity occurred. When I heard the little pop, I noticed the LCD display had turned to black lines. The phone still works, however, the LCD display is absent. Is there any way to reset the display?

In a dry climate, and you if you wear a rubber soled shoes, and when you walk on carpet to your cordless phone you will build up a static charge. When as you pick up your phone this static charge will discharge through the phone as you touch it.
The fix, avoid building a static charge by walking around without wearing shoes or move the phone to a location where there is no carpet.

I have the same problem on all the handsets and I don't know the answer to solving the problem. I just pulled out my old phone. I give up!!

This is very rare, but it looks like you are the one with ability to generate high levels of static electricity. And static electricity is naturally occurring very high voltage electricity, sometimes reaching thousands of Volts in charge. Human body is excellent conductor and as any conductor it will discharge itself when the time and place is right. Every human body has static electricity, but in most cases it isn't strong enough to interfere with everyday use things surrounding us. In your case it is different - you may not even notice it, but your discharge can interfere or even damage things. My advise to you is to buy a mechanical watch (spring driven). This should solve the problem, as the only force to have an affect on mechanical watch is gravity. And gravity is beyond any humans reach and will remain constant for the couple of million years.

VTech products are generally poorly designed and manufactured. You can probably notice the FCC Warnings on the device that say that you must accept all interference that you may recieve while in use. Go out, splurge a little, and find a telephone made by a well known company like Panasonic, Sony, etc.

If the static appears on both sets, the problem could be with the phone line itsself. If you live in a detached house you could check the line at the network interface device (NID). Its a gray box about 8" x 6"give or take and should be marked as such. (it's usually over by the electric meter.
With a screw driver open the NID, there should be a little cord and a plug that it plugs in to. Unplug the plug and plug your telephone into it if the static is still there its a problem with the line and the local telco will need to be notified. If the static disapears then its an inside wiring problem.
If you live in an apartment or condominium complex it would probibly be easier to call your telco provider and let them troubleshoot it.
Hope that helps

this is not in the phone its in the line you need to let your service provider know about this problem so they can fix it

I have found that dimmer switches might be the cause your problem. If you have any around the house you may want to change them to a regular switch.
To test to see if this is the cause, turn all your dimmer switches completely off (not just turned down). See if it clears your static issue.

As a general rule, popping sounds are bad news. This means a static charge, electrical shot, or insulation problem. Or a combination of these issues. Many times this occurs when the electrical circuit boards components break down and degradation occurs. In some cases a discharge of electrical energy (like when you get a shock from a door knob) may hop or jump between components and make a noise, whereby that popping sound occurs. In some cases, high energy discharges can cause an electrical fire, so be aware of the dangers. The fix can only be done by a professional with the skills to trace the problem and do a repair.

It sounds like you have damage to an internal component of your phone.

HERE is a link to the manual, if needed.

Time for a new phone. Most likely there are some bad solder connections and they could be anywhere. A 2 year old battery should not cause such severe problems so I'd spend the money on a new phone before a new battery.