Bitcoin ABC is like a pre 0.15.0 version of Core, but it is for Bitcoin Cash rather than regular Bitcoin.
You should actually re-install your OS. It was a big mistake for you to install any other software that isn't signed Bitcoin Core software on your computer, I would never trust fork-wallets on my main OS.
And don't forget that Bitcoin Cash's Bitcoin ABC uses the same root directories as Bitcoin Core which is a total mess, so I would use a secondary computer if possible, to install Bitcoin ABC, but if you don't have another computer, create another partition to deal with altcoin software so you stay safe, or at least an VM.
Be sure to back up your wallet.dat in case you do any mistakes.