pSX

pSX emulates the Sony Playstation 1, pretty much everything is emulated and most games run perfectly.

One thing that should be noted is that pSX DOES NOT use plugins.
The emulator is completely self contained.

The emulator has been designed to be as easy and unobtrusive to use
as possible - in most cases you will not need to configure anything
to use it (except maybe the controls).

System requirements: 

PS1 Bios, x86 compatible cpu