My TI-84 wont turn on i replaced the AAA batteries... but nothing.. would it be the back up battery needs replacing?? if i but them and still nothing what do I do

Remove all four AAA batteries. Press and hold down the ON key for at least ten seconds. Replace the batteries. Turn the calculator on.

Hello,
Here it is from the horse's mouth (TI Knowledge base)

For the TI-83 Plus Family, TI-84 Plus Family:


Caution: The resets described in these troubleshooting steps will cause a loss of applications, programs and data. If at all possible please create a backup using TI Connect™ first.

1. Try a new set of AAA batteries.
2. Adjustthe contrast by pressing and releasing the [2nd] key followed by pressing and releasing the up arrow; repeat as necessary. To adjust or lighten the display, use the down arrow.
3. Remove one of the AAA batteries. Press and hold the [CLEAR] key. While holding [CLEAR],reinsert the AAA battery and then turn the calculator on. The calculator should display the message "RAM Cleared". Release the [CLEAR] key and then press it one more time to remove the message.
4. Remove one of the AAA batteries. Press and hold the [DEL] key. While holding [DEL], reinsert the AAA battery and then turn the calculator on. The calculator should display "Waiting...Please install calculator software now". Follow the instructions for the TI83-family or Ti84 Plus family to reinstall the calculator operating system (see below.)
5. Remove all of the batteries including the round lithium battery for 5 minutes.After the 5 minute period, reinsert all of the batteries and turn the calculator on. Adjust the contrast if necessary.

Reinstalling the OS fot the TI84Plus

How do I correct the Error Waiting...Please Install Calculator SoftwareNow message on my TI-83 Plus family or TI-84 Plus family calculator?

If an operating system (OS) update fails or is interrupted, the calculator will be in an inoperable state with the message Waiting...Please install calculator software now.The most common cause of a transfer being interrupted is updating the operating system on a calculator with low batteries. Users will need touse the TI Connectivity cable and the TI Connect to send the operating system to the calculator. Make sure to have the latest version of TI Connect installed on the computer.
In order to install the software please follow these steps:
1. Connect the TI Connectivity cable between the computer and the calculator.
2. Click on Start >> Programs >> TI Tools >> TI Connect >> TI OSDownloader
3. Follow the on-screen directions to reinstall the calculator's OS.
If the message "Error! Press any key to turn unit off. Then turn unit back on." appears on the graphing calculator, quickly, remove one battery from the calculator and reinstall it while the transfer is taking place.

Hope it helps.

From TI FAQs:

What troubleshooting can I try if the TI graphing calculator will not turn on?

For the TI-83 Plus Family, TI-84 Plus Family:
Caution: The resets described in these troubleshooting steps will cause a loss of applications, programs and data. If at all possible please create a backup using TI Connect™ first.

1. Try a new set of AAA batteries.
2. Adjust the contrast by pressing and releasing the [2nd] key followed by pressing and releasing the up arrow; repeat as necessary. To adjust or lighten the display, use the down arrow.
3. Remove one of the AAA batteries. Press and hold the [CLEAR] key. While holding [CLEAR], reinsert the AAA battery and then turn the calculator on. The calculator should display the message "RAM Cleared". Release the [CLEAR] key and then press it one more time to remove the message.
4. Remove one of the AAA batteries. Press and hold the [DEL] key. While holding [DEL], reinsert the AAA battery and then turn the calculator on. The calculator should display "Waiting...Please install calculator software now". Follow the instructions for the TI-83 family or TI-84 Plus family to reinstall the calculator operating system.
5. Remove all of the batteries including the round lithium battery for 5 minutes. After the 5 minute period, reinsert all of the batteries and turn the calculator on. Adjust the contrast if necessary.

Your sure every battery was put in correctly and was good? When I first got mine I thought I had the batteries in correctly but, I didn't.

its broken

The calculator needs to probably be reset (probable). You need to leave the internal battery out of the calculator for about 8 hrs. Put it back in and then put the AAA batteries back in. Hopefully this is what is wrong and then the calculator will worik.

Could be that your calculator needs to be reset. Take out the internal battery that is located in a tiny door with a screw right above the 4 AAA batteries. Leave this out for about 8 hours and put it back in. Put in the AAA batteries and the calculator will be reset and may work.

This is kinda a weird situation. Because it's usually the other way around. Your ram will clear if your calculator is frozen. So take out all 5 batteries from the back. Even the back up battery. Then reset it again. 2nd then + then 7 then 1 Then 2. Good luck.

Try the following

1) Remove one of the AAA batteries, hold down on the DEL key while reinserting the AAA battery. The handheld might display Waiting…Please install calculator software now. Ignore this message. Remove and reinstall one of the AAA batteries again This time, do not hold down the DEL key.
2) Remove one of the AAA batteries, press and hold the [on] key for 10 seconds, release, replace the battery, then turn the unit on. Adjust the contrast.
3) Remove the AAA batteries for three hours. After the three-hour period, reinsert the batteries and turn the handheld on. Adjust the contrast if necessary.

If needed, reinstall OS by downloading the OS from the TI site and ....
On your computer, choose Start, Programs, TI Tools, TI Connect, TI OS Downloader.

(I am not the one who came up with this answer, but found it on an other site. If this doesn't work, please let me know)

Gr Marijn

Try the following

1) Remove one of the AAA batteries, hold down on the DEL key while reinserting the AAA battery. The handheld might display Waiting…Please install calculator software now. Ignore this message. Remove and reinstall one of the AAA batteries again This time, do not hold down the DEL key.
2) Remove one of the AAA batteries, press and hold the [on] key for 10 seconds, release, replace the battery, then turn the unit on. Adjust the contrast.
3) Remove the AAA batteries for three hours. After the three-hour period, reinsert the batteries and turn the handheld on. Adjust the contrast if necessary.

If needed, reinstall OS by downloading the OS from the TI site and ....
On your computer, choose Start, Programs, TI Tools, TI Connect, TI OS Downloader.

(I am not the one who came up with this answer, but found it on an other site. If this doesn't work, please let me know)

Gr Marijn