Iphone screen locked

first thing I'd have you do is plug it in and see if you get a charging display on the screen. If you still don't see anything at all hold the home button and sleep/wake button for about 20 seconds. Many times this is all it takes. If it is just a software issue you should see the screen go white with a black apple. There was an issue with the 4 in the past (mine had this as well) where at 50% charge it locked completely. This did the trick. Let me know if this doesn't work and I'll give you some more possible steps. Where did you get the phone and what carrier?

Use an external mouse to see what the device manager says about the touchpad. The device manager is in the control panel OR you can click start and type DEVMGMT.MSC and hit enter. Look for any ! or ? or X next to anything on the list.

Open the touchpad software, ASUS Smart Gesture, adjust sensitivity. Asua support : http://support.asus.com/Troubleshooting/detail.aspx?SLanguage=en&m=Q500A&p=3&s=450&os=&hashedid=n/a&no=1018

After updating OS, you may receive "iTunes could not connect to the iPhone because an invalid response was received from your device".
iTunes Could Not Connect to the iPhone iOS 10 iTunes Invalid Response...
Here are the best four methods for you to refer to fixing this iTunes could not connect to the iPhone invalid response problem, via updating iTunes and iPhone, uninstalling and reinstalling iTunes, and using iPhone alternative.

Hi,from the problem you are experiencing it's obvious that the problem is from the lcd screen,the shock it sustained when it dropped is responsible for the damage on the lcd screen again.
The solution is to replace the lcd screen but you have to be more careful with the phone,the iphone is a very fragile phone which should be handled with extra care,if the screen is replaced and you mistakenly drop it again,i'm sorry,you will have no choice but to keep replacing the screen,which is not good enough for you economically and also for the efficiency of the pone.

Thanks and take care

the battery could be scrated or even a tiny sensor thats damaged can throw everything off.

It sounds like you have some internal screen damage, your LCD may be damaged or your digitizer. A professional will need to take your phone apart and determine the cause.

The touch on the screen works as a seperate component from the screen itself. Either the lower portion is damaged and has to be replaced, or it is wet and can't sence touch as a result. The one may get better in time if the components don't corrode, the other is probably not resolvable...

just experienced it myself too, try using THREE fingers to tap the screen TWICE to reset and TWICE to enlarge again...

You have been dropping your phone so hard that the body cracked. With your second dropping, the circuits may have got disconnected. Take it to your service centre to get it going.