Cant connect to internet without wireless router

Decided to upgrade our Belkin G router to a D-link N after having trouble going thru a brick wall in our house producing slow speed on my laptop. The D-Link N software said to run it before installing the new router. But also to disconnect from the current wireless Belkin G and hook directly from the DSL modem to the PC ethernet connection. I did this but could not get a connection. Humm, bad PCI NIC card perhaps? Noticed the internet lamp on the DSL modem was not lit. So I hooked the Belkin G router up again and presto connected on the desktop and my laptop. I figured that perhaps somthing in the Belkin G was correcting whatever pci card ect the problem was. I was able to download the Dlink software to my desktop pc "nonwireless" using a dialup connection and connect the new Dlink N router. My computer and laptop both saw the new router but still no internet connection. Once again put the old Belkin G router back on and got an internet connection. Additional information. I shut down and restarted each time I connected. Even tried different sequences turning dsl modem waiting, then router waiting then pc. Anyone have any ideal? I may just be stuck with the old Belkin G. Hey at least I can get online... But really would like a stronger connection when surfing on my laptop,

if you use a standard adsl over a bt line (in the uk) i think it needs to be a pppoa
oh and make sure your using the right capitalisation as some isps are finnerky about stuff like that.