Msgsrv32.exe relays instructions from one part of your PC to another and
it is not the problem. It is reported as "not responding" because
another program either sent an invalid instruction or it failed to
respond to an instruction it received or it incorrectly interpreted it.

Figuring out which program is at fault takes some work.  This article
tells how to perform clean-boot troubleshooting:
http://support.microsoft.com/default.aspx?scid=kb;EN-US;q192926
Using MSconfig.exe, general tab, selective startup, you can narrow the
search for the errant program by narrowing the focus of where the
problem program is being started. Once you pinpoint the location, you
can remove all programs being started there and add them back one at a
time until the error notice reappears.