DSL 2780 works but can't connect to internet

[MiniPeeps]

I've just got my first ever router from talktalk, DSL 2780 which works fine but I still can't connect to the internet. I called the helpline and they checked my broadband connection is working fine and all the cables are correctly connected. Then she got me to open Internet Explorer and type in 192.168.1.1 but it brought up a page saying that it couldn't be displayed and there was no internet connection, so she told me to make sure the Work Offline option wasn't ticked and did something else in Tools Internet Options and then typed those numbers again but it still didn't work. She said something about configuring it but wasn't much help and after being passed around for 2 hours I'm still no further along.
At the moment I'm using my computer at work to get some proper help from someone who knows what to do. I really am stuck and would greatly appreciate help with this.

[2xg]

Welcome to TSF,

Have you seen this guide from Talk to Talk on how to setup their DSL device?
Wired connection setup for D-Link DSL-2780

[MiniPeeps]

I did that first but it didn't work and that's when I called their technical support line. I had another go with it all last night and discovered that where the ethernet connection is displayed on device manager there's a little yellow warning symbol which says my driver isn't installed. I'm guessing this is something requiring a disc? Can't find the disc which came with my computer many moons ago!

[2xg]

You may download the driver from your computer's manufacturer site or the network adapter site manufacturer. No need to have the CD.