EPSXE (ePSXe) is a popular PlayStation emulator that allows you to play PS1 games on your computer. It's a free and open-source emulator that's been around for many years.
Legally, the only way to obtain a BIOS is by "dumping" it from your own physical PlayStation console using specialized software. For those who cannot perform a dump, BIOS files are frequently hosted on archival sites like the Internet Archive or Planet EMU. Download Bios Epsxe 2.0.5 Pc