Many on the forum have expressed a concern over "how to" Factory Reset. For those who are not sure, here is the process for you. If you own the keyboard dock, follow the process with the dock attached. This guide can be used on any of the Asus Transformer or Asus MeMo series of tablets.
If you are just wiping the device prior to selling it or for return under warranty, you only need to follow points 1 - 5 (inclusive) in either method.
This process gives a fresh, clean installation of the most recent firmware that has been installed onto your device, so if you have updated your firmware since purchase, (perhaps from Ice Cream Sandwich 4.0 to Jelly Bean 4.1) it will not put you back onto ICS. It might take you 90 minutes to do this, but it is worth it to give yourself the best foundation for the future.
You should not need to do this again with future, incremental firmware updates.
It may seem like stating the blindingly obvious, but following this process will delete all the data on your device. By following this guide, you agree to accept full & complete responsibility for doing so.
METHOD 1 - via the settings menu
1. Backup apps & data using the Asus appbackup utility in your app drawer. I found it easier to do this in three or four "groups" of apps. Reading, Media, Games, General. Copy these backups to an external storage - microSD, SD or whatever you have. Maybe cloud storage such as Dropbox, or Box.
It is essential to save the Adobe Flash Player app at this stage as it no longer appears in the Play Store for new installations. If you need to, you can download it safely & directly from Adobe.
Adobe Direct Download Click/tap that link.
Scroll down the page until you reach the Android section, specifically "Flash Player for Android 4.0 archives" choose Flash Player 11.1 for Android 4.0 (18.104.22.168). Download the newest version of the Flash Player listed, so if there is one with a number higher than 32 in the last two digits, select it to download. It will download on your tablet.
Note that even though Adobe list this section as for Android 4.0 - this is the version to use for Android versions from 4.0 and upwards, so it can be used for 4.1, 4.2 & so on. But if you have KitKat 4.4 you will need to do some further research which this thread does not cover.
For more on this subject, please visit the Flash & browser guide thread linked from my signature.
2. Backup any other files - photos, videos, documents, epubs etc to an external storage as above.
3. Remove the external storage
4. Go to SETTINGS - BACKUP & RESET - FACTORY DATA RESET (Do not allow the automatic reinstalling of apps)
5. Allow the process to finish. When it restarts skip all the account setting up & wifi passwords etc and repeat the process twice more. For some reason it has been reported that doing the wipe three times is more successful, although there is no reason why this should be so.
6. Having reset three times, go through the new install process properly, adding your account/s & wifi details.
7. Restoring Adobe Flash player...
EITHER use the Asus Appbackup app to backup & restore this app (recommended) or, if you have the .apk...
In settings, security, allow the installation of apps from unknown sources.
Copy the Adobe Flash Player .apk file back to your device.
Open the File Manager & tap the Adobe Flash Player .apk file to install it.
Go back to settings, security, & untick (disallow) the installation of apps from unknown sources.
8. From the Play Store update any Asus supplied apps - G+ & Kindle for example, Maps etc, etc
9. Finally, restore your photos, docs etc & reinstall your apps from the backups, one group at a time & cold boot between each group that you restore. (Unless you are resetting because of system instability. In which case, read the next section, first.)
10. Now do a Cold Boot (aka Hard Reset). This cleans system caches, but does not delete any user data.
Unplug the power cord and shut the unit off. Press and hold the VOL DOWN and then POWER button at the same time for at least 10-12 seconds until after the start-up screen appears and is joined by some small print at the top left of the screen then let them both go. If the TF booted the way it always does, you have not accomplished the task, try again until you have seen the 2 icons, (if you have Jelly Bean there will be 4 icons, the left most being RCK, which is correct), in the screen.
After a few seconds you should see a couple of shapes in the middle of the screen called "Wipe Data" and "Android". The right "Android" will have a green highlight fading in and out. Wait a few more seconds until the term "Cold Booting Linux" appears in the list near the top of the screens and let it reboot. If you own a keyboard dock be sure you do this with the dock connected. If you are using JB there will be 4 icons, disregard the 2-4 icons unless instructed and the 1st icon (RCK) will be flashing..
If your TF is on 4.2 press vol down key to choose middle Android icon & once you do that press the vol up key, that will start the cold boot process.
This applies to all TF models, however, if your Prime or Infinity are locked up, there is a reset available using the hole just below the SD Card slot, this is NOT the same as a hard reset.
Resetting for stability?
Be careful about restoring your apps from the backups. If you are suspicious of apps causing stability issues, then only restore apps slowly, checking for stability as you go.
METHOD 2 - via the power button/volume keys
If you are unable to power off, try this process from point 2.
1. Unplug the power cord and shut the unit off.
2. Press and hold the VOL DOWN and then POWER button at the same time for at least 10-12 seconds until after the start-up screen appears and is joined by some small print at the top of the screen, then let them both go. If the TF booted the way it always does, you have not accomplished the task, try again until you have seen 2 icons (ICS), 4 icons (JB) in the screen.
3. After a few seconds you should see some icons in the middle of the screen - in ICS they are called "Wipe Data" and "Android". The right "Android" will have a green highlight fading in and out. In JB there are four, the first of which is RCK.
4. Press the VOL DOWN button to select the "Wipe Data" icon then VOL UP to confirm it.
5. The system should then Factory Reset as in the "settings" process (method 1). Go through the new install process, adding your account/s & wifi details.
6. Follow method 1, starting at number 7
Thanks to forum staff member Leeshor for the cold boot/hard reset process