My phone says no link to base but I am right beside it.

Sounds like the antenna on the base station is not receiving, or the cordless handset is not transmitting -OR- the sets have never been registered to the base station (please look up registering to base station, if the set has never been registered)

Did the cordless set work before?

The base station or the handset may just have a hick up, I would un-plug the base station and leave it un-plugged... now get all the cordless set(s), and take out the batteries from the cordless set(s). Wait for about 15 seconds for all the power to drain out of the sets, then re-install the batteries.

Once all the cordless sets are back up and working, plug in the base station and wait for about 1 minute.
This forces the base station to re-establish and link between the base station and the cordless sets.

Good luck

The procedure in the Panasonic manual (http://service.us.panasonic.com/OPERMANPDF/KXTGA101.PDF) will NOT work if the phone has been previously Registered. With some experimentation, I discovered the procedure to Register a handset previously Registered on a different system, which must be initiated at the handset. I was able to successfully Register the handset, and all is fine.
I experimentally DEregistered the handset (from another handset on the system, once it was successfully Registered) and once Deregistered, the phone ONLY displayed a prompt to begin Registration, even after removing and re-installing batteries. So this is what the manual expects the user to encounter when the phones are first unboxed when new. Again, the procedure in the manual does NOT apply to a used phone.
So that you can share this with future buyers of your other handsets:
TO REGISTER A USED KX-TGA101S HANDSET:
1) On handset, press "Menu"
2) Scroll down to "Handset Settings" and press "OK"
3) Scroll down to "Registration," press "OK"
4) At "HS registration" prompt, press "OK"
5) Phone prompts "Press LOCATOR on base for 4sec Then press OK."
6) Press "LOCATOR" button on Base Unit for four seconds until Base begins to repeatedly beep.
7) Press "OK" on handset.
8) Phone will display "Registering" for a few seconds, then will beep and display number of unread messages.
9) Phone should now be registered.
NOTE: Deregistering the number of a missing handset (1,2,3...) allows replacement handset to assume that number for Intercom use. The Deregistration command is one scroll down from "Registration" in Step 3. EXAMPLE: Replacement registered as #5, was intended to replace #1 of four handsets. On handset #2, Deregistered #1 and #5. Replacement immediately entered Registration mode - proceed from Step 6.