Looks like you have SQL (express or full) installed which prevents the install package from successfully installing and configuring SQL 2014 Express for WinCC (and TIA Portal).

Brandenquality

Hi, I am trying to install tia portal v15.1 however I got lots of errors while trying it. I attacted the log file as txt format, .log is not supported here. I tried the solutions already given in this forum such as removing winCC program, or not installing winCC extension at setup. However the number of errors I get increases with anything I do. I tried to install it at virtual machine too but it gave the same errors. Please help me I really need an answer quickly. I have a project to finish for my school. Thanks. 

You can ZIP the log file. There is perhaps one expert which knows what to do with it. No guarantee that you'll get an answer though. 

Strange that the install on the clean (?) VM does not work. Which Windows did you use? Win7 would be the most stable, I would guess. Thereafter Win10.

Do try to trigger the admin rights for the installation and have all security / anti-virus switched off. Be sure to have English or German selected as usage language with you native language (if not English / German).

But finally - There are several SQL related install errors that are mentioned within this forum. Best for you to use the search facility here and attempt to find them.