Petrabros.exe

cant find out how to rid myself of it. any pointers? tried defender(after i got it to work), CCleaner, ad-aware, malwarebytes, regedit.

Hi:

That seems to be a very old malware variant (a Google search turned up hits from as far back as 2001; without seeing some sort of scan log/file path, one cannot be sure that these are the same thing).
That's probably why Malwarebytes did not see it -- MBAM only targets current malware in the wild, typically less than 3 months old.
And CCleaner is not a malware cleaner, so it may not see it, either.

I wonder if any of the current anti-virus or anti-malware applications will detect it.
You might try the ESET Online scanner (it's very thorough).
Panda and Zemana also have 2nd-opinion scanners.

Another suggestion might be Revo Uninstaller.

If all else fails, you might need a trained malware expert to assist you with a custom script.

>>Before doing anything major, I would create a system restore point and (perhaps) backup the registry.

MM