I have a D Link router and I haven't had my laptop for some time and I just bought a new one and my problem is I didn't write down my pass key to get connected , what can I do

Easiest thing to do is reset everything to factory defaults. This will wipe out all of your router settings and remove the security password required to access the internet. But once you've done that you can go into admin mode and set it up again.

That being said, the reset button is typically on the back of the unit. Look for a small hole, possibly with a red center. Gently push the end of a paper clip into the hole until you hear a soft click. Gently hold the button depressed for about 10 seconds.

You may have to cycle your modem first, wait until all lights are doing what they should, then fire up the router. You should see a wireless network with a great signal strength. That would be you.