help with asus transformer prime

[mjsdhs]

Hubby bought me a prime for valentines day and i love it i have questions though.

How do i know what operating system i have?

Is there a place i need to go to update or will the tablet do it on its own?

The keyboard will freeze ...why?

Do i need an antivirus program?

And last why does my twitter window keep shrinking?

Thanks.....