I have a Garmin nuvi 255W GPS, when I turn on this GPS, the "AGREE" button turns to yellow, it should be green, when it opens, I cannot click any buttons, how can I fix this problem?

SOURCE: My Garmin Nuvi 255w Car Gps

You must call Garmin at 1-800-800-1020 they will walk you through plugging in nuvi to your computer (must have usb cord) and it will upload then go to my computer and choose garmin drive then click garmin folder and either find the folder they say or make new one like I did with the guy on the phone and put in code. The only information needed is the numbers on the bottom of the device.... super fast fix!

SOURCE: Garmin Nuvi 255w freezes

mine would constantly cycle in the reboot. I had to clear the stored data by pressng and holding the lower right side of the screen and turning on the gps. once it boots up, it will ask if you want to clear the data memory (will not clear the actual maps). say yes, when it reboots, you will have to redo your personal settings as if it was new out of the box.

SOURCE: Garmin nuvi® 255W Car GPS Receiver. Problem: Reboots during Map

The simple way is to send the unit to Garmin they will load the maps for free.
If you keep trying - try this -

With your thumb in the lower right corner of the screen - pushing in - like there is an X there - [ push with your thumb before you turn it on] Turn it on -
when this screen comes up - push YES -

then try your maps.
If they do not load on your pc [ which must have the unit hooked up and a legit copy of the newest maps ] then send the unit to Garmin. They will load your maps for you FREE.

SOURCE: nuvi® 255W Car GPS Receiver: The screen of my Garmin nuvi 255w GPS is white and...

Press and hold the lower right corner - then see second picture

SOURCE: nuvi® 255W Car GPS Receiver: Can I get a owners manual for the Garmin nuvi 255W...

Hello.
You can find the garmin manual here.
Just type in your unit details.