How do I get wifi to work after the service guy has left

In order to get WiFi you must have access to a supplier.
If you have a computer and a router with WiFi you are ready to go.
Press Apps > Settings > WiFi
This will show you all the Wi Fi suppliers within range.
Click on yours and enter the password
Do the same routine when using a free WiFi service on your travels , MacDonalds for example. The password will be on display or ask a member of staff.

Please note that log-in password and wifi password is not the same, to be precise. However, if you are using the default Windows interface to connect to wifi networks, as opposed to a third party software (i.e. one that came with your wifi card), the password can be recovered. The procedure can varies a little bit depending on which OS you are using. Assuming you are running Windows 7:
- right click the network connection icon in the system tray and choose the second (and last) option;
- when the Network and sharing center window opens, in the left hand pane, choose "Manage wireless networks";
- a new window pops up, where you will find a list of saved wireless networks. Right click the one for which you want to recover the password, choose Properties;
- click the "Security" tab, tick the option to show the password, and you can read the password in clear text.

Go to WiFi settings on your tablet
Look for available networks
Is your old network available? My guess is it is gone.
Select the strongest network in the list.
Use the password the technician and you made.

Confirm you do not have caps lock on, or are on a laptop with numlock on first. Assuming those basic settings are off, next you want to try and add the password in cleartext. In the wireless list, right click on your wifi network and select properties. Underneath the network security key should be a check box that says show characters. Click that and your password should be readable. Confirm it's correct or retype if not and try again.
If that does not work you may need to log into the router itself and reset the wifi password.

If you look on the Kindle's Home page, it should show a battery on the left side. There should be a ramp of bars to the left of the battery showing a few darkened bars and to the left of that the word Wi-Fi should appear. If it does not appear, does the word "off" show to the left of the battery icon? If yes, select Menu and Turn Wireless On. If neither of these appear, then the Kindle might not support wifi. If you have never been able to connect wirelessly anywhere with the Kindle, then you probably need to get in contact with their help desk. If you have been able to connect to wifi before, then I assume that you know how to use Menu to select Settings on the Kindle from the Home page, select the wifi from the list and connect to the wifi of your choice using passwords etc., so your problem is with the router and you would have to troubleshoot that. Does wifi work with anything else, etc. One thing you can try if the Kindle has previously worked on wifi is to press and hold the on button for 20 seconds to cause the unit to reset. However, if the wifi isn't working, I think this will make the Kindle unusable because I think it reloads a bunch of stuff from the internet. The Kindle user's guide should describe what to do and whom to contact.

The factory default password should be 4000. If thast doesn't work you will have to reset or display the admin password in service mode.

To enter service mode hit the ststus button and then type 10871087. Scroll through the menu with the * and # keys. If you make changes in service mode and do not know what you are doing you can cause the copier to permanently fail.