Whenever I try to send stuff to my calc I get a "Access is denied" message.
I have been told to just change the batteries, and it worked before, but now it doesn't no matter what I do.
Any Ideas?   

What calculator are you using? Are you using tilp or ti-connect? What OS are you using? ( Both calc and comp ).
Whatever other information you can think of to give us will help us help you.

I am using a TI 84+ SE, OS 2.43, my PC is Windows XP, and I am using TI connect.
I can't think of any other info that would be useful, other than random stuff.
It is 2 years old, and I installed TI connect about 6 months ago when I started programming.
Hope that is enough info.

Have you ever been able to send data between your calc and comp? What exactly happens when you try to send a program between your comp and your calc ( both to and from )? Have you tried all variable types? Have you modified your certificate in any way recently? Have you installed anything on your calc that modifies the OS too?

First of all, I have been able to transfer data back and forth in the past.
When I try to send data either way, it says "transferring...", and then it says
"Access is denied" and under it it has some weird big number.
If by variable types you mean the file types like .8X, .8XP and stuff like that, I have.
I do not know what modify my certificate means, I am not that smart.
And as far as I know, I haven't done anything to modify the OS.
Also, what is a calc driver? and where do I get a new OS? (is it on the cd or on the net?)

Sweet, thanks. I will try all those tactics, and hopefully one will work.