What is the importance of mobile application testing in today’s scenario? Also, explain the entire process and steps involved in carrying out mobile application testing.

When doing performance testing for a particular project, what are the factors which need to be taken into consideration while selecting a tool? Also, if there is a choice of opting between JMeter and Load Runner for performance testing, which one can be considered?

Which are the different automation testing (software testing) tools which are available in the market? Also, with the emergence of various automation testing tools in the market, will the demand for manual testers reduce considerably in the future?

The most common type of error that we see is error 404. Can someone explain to me what exactly it is and why is it so common? Is this an error caused because of some fault at the client-side or server-side?  

Can someone explain to me what bad Gateway error means and why does this happen? Is it a client-side error or a server-side error and would it cause any problem in the network?

Can someone explain to me what does the error 504 mean and how it can be fixed? Is this error caused because of the Client or the server?

Can someone explain to me why a system crashes, and the error message is displayed along with it in a blue screen especially for a Windows operating system and the various way how a system denotes this crash?

I have a Windows PC, and recently I had got an error message on my computer saying that a fatal exception has occurred along with some code and my computer shut down unexpectedly. Can someone explain what went wrong and how to solve this problem?

I use Windows PC recently I get a device error when I try to use my USB. But the USB works fine when I use it on another computer. So what is the problem here, and how can I resolve it?

I have a Windows 10 PC, and sometimes I get missing DLL files for a few programs that access system files. Can someone explain to me what a DLL file is and how I can correct this error?