The application is unable to start for libstdc++-6.dlI missing

Hi!
After I get this DLL error it seems like it appeared to all my usual software. I copied all the DLL files in my system32 and rebooted the PC. Now I want to run a DLL fixer but someone told me this is not a good idea because I can harm all my DLL files. Please tell me what is the best way to solve this error message? How can I fix this DLL files error?
Thank you!

core.exe – Unable To Locate Component
This application has failed to start because libstdc++-6.dlI was not found.
OK
