bushboy

Hi everyone i'm hoping i've posted this in the right place & hoping someone can help me as i'm a bit lost on wot to do next. Basically i have just home & am having trouble with network & sharing. At my old home my ISP was AOL & i had a speedtouch modem which i just plugged 2 ethernet cables into it & the other ends into my desktop & laptop, then went into network & sharing centre & turned on network discovery, file sharing & public folder sharing & made sure the network was private network, then i would just click network in the start menu & i would see the other comp. Right now moving to my new address we have virgin as our new isp, some bloke came around to install it all whilst i was out but it's just a samll virgin modem which my comp plugs into with a ethernet cable, he also left a wireless box with a installation disc which i ran so now the small modem runs into the wireless box with a ethernet cable & the both my desktop & laptop run into the wireless box again with ethernet cables. We have no problem getting on the net on each computer but on my desktop when i click on the network through the start menu a tab drops down saying that network discovery #& file sharing are turned off. Network computers & devices are not visible. Click to change... so i do then i get a option to turn it on but when i click on that & click continue it does not turn it on but the drop down box drops down again. I have tried also going into the network & sharing centre to turn it on but when i do nothing, the option stays on off. Couls someone please advise me on how to get it working please? Thankyou in advance