needless to say i did some incredibly stupid things like accidently opening up a .ytd file with winrar and long story short every vehicle skin i try to download shows up as a zip file. is there any way to reverse this? i went back a restore point and my gta is fine but now any .ytd file i try to download from now on is a zip file which isnt compatible. Like i said very very foolish of me and im ready to accept the consequences

Just right click the file, and select "Open with..". Select the program you want to use and check the checkbox to always use that program. You're all set. Tbh, you should still be able to open it with OpenIV without issue. Changing the default program for a filetype doesn't always mess things up, so going back to a restore point might have broken more for you than it fixed.