If you have restrictions on your router or if you need to change something and you don't know the password, or if someone has taken over your router maliciously, the process to recover the password is relatively simple. If you know all your ISP details, and you can afford to completely reset the router to gain access and reconfigure it, then read the article http://www.infobarrel.com/How_to_Reset_and_Reconfigure_a_Router . If someone will notice that it's different then use this method.
Start by going to the "Sniffer" tab. Go to configure at the top menu bar. Make sure the right device is selected; it's usually the one with an IP address and a subnet mask. Make sure the "Don't use promiscuous mode" is checked, and the "start sniffer on startup". Now click apply, then ok and return to the sniffer tab. Make sure the sniffer is activated by clicking the button under the menu bar right beside the open folder. Right click in the empty lines, and then press scan MAC addresses. This will bring up a little window. Usually the default settings work, but if nothing comes up after scanning, go back and change from all hosts to range. Now change the last number in the first line to 0 and the last number in the second line to 255. Now scan again. This will bring up a list of computers and devices connected to the network. If you right click on one of them and click resolve host name, it will usually tell you, and you can use that to check if it's the right computer you're sniffing on.
It will start to overlook at the activity between the computer and the router. You can move on to the next sub-tab at the bottom, the one called "passwords". Under the HTTP section all the network traffic should be appearing. Passwords and username from a router is not encrypted so you won't have to crack it. Now all you need to do it make the person with the password type it in. When they do, it'll show up in the screen. There you go. Now type in 192.168.1.1 in a web browser and you'll be ready to reconfigure or change the settings on the router.
Do not use this for malicious purposes, but instead as a way to defend yourself against malicious people.