I have just come across a rather weird one that might interest you
The machine is a Pentium/ 128Mb RAM running WinME (fully updated) IE6 (fully patched).
On boot up it would either attempt to run scandisk and stall, or start the boot up and windows desk top load, then stall. On looking at the processes msgsrv32 had stopped responding. (sounds familiar?)
The strange part is that the system will boot if you go into safe mode, let scandisk run, then do a warm restart!
On powerdown, the "it is now safe to turn off your computer" message appears. On the next start up it attempts to run scandisk and stalls as previously described.
I have discovered that disabling the firewall (ZoneAlarm) automatic load on boot up, letting the machine boot, then starting ZoneAlarm manually resolves the problem and the machine boots and runs normally.
I am still trying to find out what ZoneAlarm is conflicting with.
The symptoms were so weird I thought they deserved a mention