If you pressed the reset button at the rear of the router then you will have most likely wiped the configuration settings, including wireless, and set it back to Factory defaults. If so, depending on the actual model DLink number, wireless may not activate until it is configured to do so.
(I own a DLink DI-624 model and pressing the reset button on that particular unit wipes and deactivates the Wireless, which then requires reconfiguration via a LAN cable)
If that is the case, in order to carry out a reconfiguration to activate wireless you would need to connect the router to your computer via a LAN cable and then either use the DLink Easy Installation configuration program or perform it manually via a Web browser.
The 'Easy Installation' configuration program for your router model number should be able for download from DLink support web site:
http://www.dlink.com/us/en/support
Some general configuration info on how to go about manual configuration of a DLink router is available here:
http://www.ehow.co.uk/how_2091714_set-up-dlink-wireless-router.html
For clarity, what is the actual router model number?
Is the DLink a router that was provided by your Broadband Service supplier? If so, you could check with their support area for further advice.