Problems with wireless router

[homeslicezero]

I got an Ativa Wireless-G router not too long ago, and since i connected it i've been having problems streaming music and video, downloading, and a load of other things. It also disconnects from the internet out of nowhere, and I have very bad lag spikes on PC games.

I have 2 PCs right next to eachother, both wired to the router, and I have a laptop wirelessly connected. I'm inexperienced with networking and routers, etc. so I need help .

 

[hiren]

your laptop has problem?
two wired pcs are working properly?
Was the wirelss working properly before?
Is other things working fine other than music and video?