Emulator on PC Help

So I got a new computer and can't seem to find out why I can't work my emulators.
Well, my emulators work it's just my roms don't work. Before when I downloaded
them (roms) they would save as a zip file and they would work just fine. But now when
I download them (roms) thet download as a 7z file. Could someone help please?

Use Winzip or Winrar to unzip the roms.