If you had a PC in the 80s and 90s, you learned to expect certain sounds—the whir of the fan in the power supply, the gentle chittering of the hard drive, the grinding of the floppy drive checking for a disk, the satisfying beep! of the PC passing its power-on self-test. And, if you were lucky enough to install Windows 95, you eventually got that lovely sound composed by Brian Eno.
http://mentalfloss.com/article/57030/listen-1993-pc-boot
