The SMART error is an automated diagnostic error that detects impending failures in a hard drive. This is indicating your HD is about to fail and needs to be replaced. I believe this is the correct iFixit hard drive replacement guide for your computer. If not, the designs haven't changed much (internally, at least.) As for data recovery, you can try placing the "bad" HD in an external USB enclosure and seeing if your recovered mac, or another mac, will be able to read it. If not, you may need to seek out a professional data recovery service. Seagate does offer data recovery services. Let me know if you have any follow-up questions. Good luck.
This is typically caused by the headphone activation trigger being stuck. Your phone thinks there's a hands-free headset plugged in. You can check this by playing music on the iPhone; if it doesn't play through the speakers, the headphone trigger is stuck. Without opening the phone, the only "safe" way I know of to resolve this is to blow compressed air into the headphone jack. If you feel like opening the phone, disassemble the phone until you can see the inside of the headphone jack. Dab some contact cleaner on the trigger and push it back and forth. Good luck.
Have you tried cleaning the screen with some screen cleaner? Be sure to use actual screen cleaner, not Windex. I have had instances where oil/grease buildup on the screen registers touches under the smudges or keeps the touchpad from seeing my actual touches.
This appears to be an issue introduced in WebOS v3.0.4. Others are having the same problem. Accelerometer Issues after 3.0.4 update ---TRY THIS 1st--- HP recently put out version 3.0.5. I saw nothing in the changelog regarding the accelerometer, but you can see if this fixes the issue. LAUNCHER-->SETTINGS TAB-->SYSTEM UPDATES ---TRY THIS 2nd--- You can also try running the diagnostic test for the compass. It may not work, since the compass and accelerometer should be two separate modules, but it's the closest test to an accelerometer test. LAUNCHER-->SETTINGS TAB-->DEVICE INFORMATION. Once in Device Information, tap on the "Device Info" tab on the upper left of the screen. Select DIAGNOSTICS. ---IF ALL ELSE FAILS--- You can use WebOS Doctor from HP. this link will tell you how to use it. Download the 3.0.2 version from WebOS Internals. That will downgrade your tablet back to 3.0.2 which should resolve the issue. Good luck.