Network bridge - Windows 8 - wired and wireless

Hello,

Ok, so here is my setup :

- Desktop PC connected through ethernet to my DSL modem/router. Network "ABC" (internet). The desktop is ALSO connected to network "XYZ" (no internet - home network only).

- Hi-fi amp connected through ethernet to network "XYZ" to a regular router. I have to have a wired connection to the amp.

-Android phones connected to XYZ.

- Laptop connected to ABC (for internet access)

My goal is to be able to use DLNA to stream my music collection (stored on dekstop PC) to my amp, which I achieve to do if I only log my desktop to network XYZ. I've tried crerating a network bridge (Win 8 pro). Now, I thought this would work perfectly, but laptop won't connect to network ABC (modem returns an error, says Windows).

Also, I'm using a Thomson TG585 modem/router... I noticed that the lights seems to freeze and I can't access the modem firmware through its ip, even if the ethernet light is green.

More info : I had to manually assign the DNS adress on the desktop computer, but managed to connected to ABC from my lapop without touching DNS.

All in all, my networks seems to work in bits and pieces, and behaves eratically. Not sure what to do.

I'm on the verge of buying another modem/router, but I'm not sure if this would really help to fix my problem.

Any help would be appreciated...