so whenever i go to winRAR it says i have to pay and that my trial was done i haven't payed yet and i can still use it is that ok? or will it do something bad?
Best answer right there. Been using 7zip for years. There's no reason to pay for ZIP or RAR software. Feature packed and supports many compression file formats, including RAR. So you will still be able to open your RAR files after you uninstall WinRAR.
To test, install 7zip first and see if you can open them before uninstalling. If yes, then you're good to go.
and how similar are winRAR and 7zip i mean can i do the same stuff like all i really do with winRAR is download stuff on it like demos for games and other stuff