And I know why. The 741 is an operational amplifier, most likely used to boost the analog audio signal. Since it is a totally analog device, it does not need drivers. You need drivers for the chip behind it, the D/A converter. Most likely an AC'97 codec...

Ask your friend what type (or brand) of mainboard he/she is using. The type and brand is generally printed on top of the mainboard somewhere. Check at the corners, and between the slots (PCI/ISA, where the video/sound/modem cards go in).

As soon as I have a mainboard type, drivers should be found within the minute...