Does anyone know if there is a specific audio codec buried somewhere in the MSN 7.5 software?  I have tried everything I can think of do get rid of choppy distored sound on PC running Win XP SP2 with all updates.  Audio works fine for playing CD-ROM, mic on the PC feedback on speakers.  I tried putting in a PCI audio card and bypassed the MoBo sound (ESS 1969 or something).  No difference only the MSN audio is chopped up.  The video channel is fine, but is always kinda slow (on all my PCs).  I have the latest version of MSN 7.5.0324.  Fairly sure there is no problem with router or firewalls as two other PCs behind this router work just fine on MSN 7.5.

Have you tried Winows Live Messenger?

also, if your using plus! you will need to get the new Mesenger Plus! live.

Or just do a repair installation of Messenger 7.5.