I must change my SSID password in my D Link router DI-524.I suspect that someone is getting in my system without my consent.My system is much slower than usual.D Link is not offering on line help for this problem.
Thank you for your help.

Press the reset button (shown in the photo) using a paper clip. Hold for about 10 seconds, then release. All configuration settings will be reset and you can set up the router as if it were brand new.

Here is a link to the manual if you need it:
http://www.dlink.com/products/?tab=3&pid=DI-524&rev=DI-524

Good luck,
WallyH