Yes you need the SETUP.EXE file for the re-installation or if you have also deleted the setup also then you can use a free program called RECUVA which will restore your accidently deleted files on the same drive
Here is the link to the program http://www.filehippo.com/download_recuva
I have a similar problem. I uninstalled accidentally an Nvidia drive which came with my desktop. It's a Gateway Lx4720-2m.I tried to install a drive from the Nvidia page, but it said something about not having the right hardware. What can I do?