The Ultima V Upgrade Patch adds music to the IBM PC version of Ultima V. In 1988 sound cards were uncommon on the IBM-PC, but other computer game systems included a full soundtrack for the game. This patch updates Ultima V to the standards of the C-128 version, however with much higher quality. Also, the song from the Amiga version is added to the character generation.
The patch can be downloaded from exodus.voyd.net.
DOSBox is one way to get the DOS sound drivers working properly.
One problem is, that the u5cfg.exe needs dpmi, which DosBox doesn't provide. You can find a substitute here. Unpack it and make sure that all the files are in the root directory of the game (no sub-folders). Now the u5cfg should work.