This is a consolidation some of the more frequent issues with the Transformer.
Cold Boot (aka Hard Reset)
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..
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.
If your TF is on 4.2 press vol down key to choose the middle Android icon & once you do that press the vol up key, that will start the cold boot process.
A cold boot [AKA hard reset] does not delete any data.
Battery (charging/power) issues
If you don't feel you are getting the best run time from the battery, first try this. Run the TF down to the point it turns off. Then charge it for 8 hours. If the battery is giving you other problems like it doesn't seem to want to charge, follow these suggestions. Pick what applies best to your problem.
1. Check the charger to make certain it is seated in the AC socket. If necessary, take it apart and spread the pins apart and try again.
2. Another thing to try is putting the charger in the freezer for 20-30 minutes in a ziploc bag.
3. Plug your TF, using the charging cable, into your PC for 2 or more hours.
4. If you sense some electrical charge around the rim of the TF when charging it may be a polarity issue with the charger. If it is a 2 prong charger just turn it 180 degrees. For further info (RS link)
First go to Settings - Location - GPS, make certain the GPS location is ticked. It frequently takes several minutes to as much as 15 minutes on the first try get a GPS fix.
Get GPS Test or GPSFIX from the market to see if it is working. A further test, one I like, is to get Google Sky Map, (free from the Market) and take your TF into an area with a clear view of the sky. Turn off the WiFi if still connected, and wait until you can see the sky you are looking at in TF screen. Pointing at a bright star or the moon helps.
The TF does NOT need WiFi for the GPS to work, (some tablets only come with GPS in 3G versions but this is not the case with the TF). It does, with the default Google Maps, require WiFi access to plan a route, (unless you are using a purchased routing app), which will then be automatically cached. So long as you don't deviate from that route the TF will work just fine. The better idea is to get an app like CoPilot or Sygic (neither are free), that will allow you to (pre) download maps of specific areas. The first time you try to get a GPS fix, be patient as it may take some time.
Firmware update Issues
If updates are not appearing as expected, try going to Settings - Applications - Manage - All - DMClient - Force Close/Clear Data/Clear Cache and then reboot. Next, go to Settings - About - Check for update.
If that doesn't work, download the correct firmware from ASUS, (follow the links in my signature). Extract the first file to the root of a MicroSD card. Insert the card in the TF, power down then back up. The TF should find the firmware and update. Make certain you are using the firmware specific to your location and device. Your MicroSD card will need to be formatted as FAT32
If you are having issues with Market updates, Clear the data in the Market: Settings - Applications - Manage - All - Tap "Market" - Force Stop, then Clear Data
Open the Market (may need to authenticate your Google account again)
iTunes music on your Transformer.
Getting music from iTunes on your desktop to your TF, on or off line
First, on the system with iTunes installed sign up for the Google music beta. music.google.com. Your iTunes music will get synced to Google, give it some time.
Go to the Music app on the TF and you should be able to stream the music from Google. To sync the music to your TF for off-line use, When you see the music in the music app you will see a small triangle you can tap that will allow you to select "make music available offline"
There are also a few apps to let you listen to your music on your local network, DoubleTwist and AirTwist and iSyncr work well