How can I get rid of the dead spot on my screen?

A few days ago the lower part of my device's touchscreen went dead. Whenever I touched the bottom 2 to 3 centimetres of my screen, it simply wouldn't respond, meaning that the spacebar and a few of the letters on the keyboard didn't work, along with the buttons in some apps. So I did some research on Google, tried a few solutions ranging from performing a soft reset to taking the phone apart and making sure all the parts were connected correctly, but no luck. A few hours later, my phone ran out of battery and when I restarted it the problem had gone, only to return about 15 minutes later. Therefore, I'm pretty convinced that the problem is software rather than hardware based and am reluctant to perform a hard reset or to replace the digitiser. What should I do instead?