Download the client again and try to start the .exe file. If it still doesn't work deactivate your firewall or put the pro folder on the exception list of your firewall and try to launch the .exe file. I don't know if it will work but you can try it.

many reason why it won't work

first try to install c++

https://www.microsoft.com/en-gb/download/confirmation.aspx?id=14632

All solutions here.

 

1. You have anti virus blocking/removing or scanning this file at the time.

 

2. You should try the 32bit version instead of 64bit.

 

3. You are missing the c++ runtimes which most games and things install when you install games.. or windows update has them too. you can get the required one here. (Run the 64 bit version after this) https://www.microsoft.com/en-gb/download/confirmation.aspx?id=14632

 

4. You have moved, or do not have the PRO32/64_Data folder with the game EXE..