iTunes windows looses connection to AirPort Express - problems with speakers menu

About every second day the iTunes on Windows looses the connection to the Airport Express and I cant switch it on again in the menu for speakers. This now happens since months! The only solution I found so far is to reboot the windows computer, but I am really tired of rebooting.

More details:

We listen to music in two rooms simultaniously, one sound system is directly connected to the PC, the other to an Airport Express.

About every second day the iTunes connection to the Airport Express gets lost. In iTunes the popup window for speakers still shows both items, and both check marks are checked, but the Airport Express name is grayed out. When I then click the checkmark for the Airport Express away, the menu disappears completely.

At this situation, the menu on any iOS remote control disappers too.

Relaunching iTunes does not help to make the menu appear again.

Switching the power of the Airport Express off and on does not help to make the menu appear again.

At the same time, when I launch iTunes on a Mac, this one shows the speakers menu, and I can switch the checkmark for the AirportExpress on, but it only influences listening to music from the Mac, and does not change the situation for listening to music from the PC. The PC still does not show the menu, still does not play sound through the Airport Express.

The only solution that I found so far for the windows iTunes is to reboot the PC. I am so tired of rebooting.

Is there maybe any service I could relaunch? Anything else?

PS: happening with Windows 8, but we had the same problems with Windows 7 before too. iTunes is always up to date.

Please help!

thx, ullala :-)