New T720 Owner HELP!!!!

I've recently purchased a used T720. Worked fine the first day, today after accidenty hitting Web Browswer and then Cancel (the red button), it seems as if it does not want to read information from my SIM card.
It will not allow me to go into Messages, or Phonebook.
When I choose these it says "Please Wait" with an hour glass, and does not do anything at all.
When trying to enter Calendar/Datebook, it says "Busy! Try Again" and bounces back to the main menu.
I can dial numbers in, but cannot look numbers up (obviously) and if somebody calls who is programmed into the phonebook, the number shows, but the name does not.
I have tried taking out the battery and SIM card and putting it back together.
Nothing has helped.
Thanks for any advice or help you can give me!

It sounds like you need a new sim card, I would definatly have that looked at

The first thing I have to say, is SHAME ON YOU, for buying this phone in this day and age. There is absolutely no excuse for that...especially as an Americain, as you people have a lot better phones out there for practically as much as you paid for that phone.

Having said that...

do the following.

Power down
remove sim
wait 10mins

insert sim
power up

check functionality?
YES, GREAT
NO, CONTINUE

do a master reset
power down
power up

YES, GREAT
NO, CONTINUE

remove sim and test it in your friends phone. Does it work?

YES, GREAT, now you can get yourself a new phone
NO, CONTINUE, you'll need a new sim card.

While your at it you may as well put your friends sim into your t720, which inevitably at this point SHOULD work, as you've established your sim was the cause.

I think the phone is defective & not the SIM card. That phone isn't even made anymore so I would strongly recommend purchasing a more updated used phone like the V551 or V220.