Texas instrunment

How do I reset the RAM on the TI-89 or TI-89 Titanium?
 
The instructions below detail how to reset a TI-89 or TI-89 Titanium.
 
Press and release the following keys simultaneously: [2nd], leftarrow, right arrow, and [ON]
 
OR
 
Input the following sequence:
 
      • Press [ON]
      • Press [2nd]
      • Press [6] (MEM)
      • Press [F1]
      • Press [1] (All)
      • Press[ENTER]

How do I correct an Illegal Instruction error on the TI-89 or TI-89 Titanium?
 
Some 3rd party operating systems (OS or shells) and games can cause an Illegal Instruction error message todisplay at the top of the screen. 3rd party software is not supported by Texas Instruments and Texas Instruments would advise against their use.
 
This issue may be corrected by reinstalling theoriginal OS on the calculator using the TI OSDownloader which is installed with the current version of the TI Connect™ software . To do this please follow these instructions:
 
• Remove one AAA batteryfrom the TI-89 or TI-89 Titanium.
• Press and hold the [Apps] key
• While holding that key reinsert the battery
• Press the [9] key
• Open the TI OSDownloader program. (This can be found in: StartMenu\Programs\TI Tools\TI Connect\TI OSDownloader)
• Run the TI OSDownloader program to reinstall the operating system on the unit.

How do I reset all the variables back to zero on my TI-89family, TI-92 family, or Voyage 200 graphing calculator?
 
The instructions for clearing all variables and resetting them back to the default value on the TI-89 family, TI-92 family, or Voyage 200graphing calculator have been provide below.
 
To clear the variables on the TI-89 family:
 
Press [2nd][F6]
Choose 1: Clear a-z
Press [ENTER]
 
To clear the variables on the TI-92 family or Voyage200:
 
Press [F6]
Choose 1: Clear a-z
Press [ENTER]

I have lost my applications on my calculator.  How did that happen?
 
When performing certain operations with the TI-89 family, TI-92...