I bought a Curtis klu on sale and was impressed. Added google play, downloaded a few apps. Worked perfectly until I downloaded a ePub free book from another site which wasn't what it appeared to be. When attempting to open, all these internet ads flashed on the screen causing it to freeze so I did a factory reset which seemed to work but at restarting the tablet, the hard drive made the dreadful grinding noise. It is working fine now and I ran Lookout and no virus. I understand that resetting doesn't exactly solve the problem. My question is; do you think this is the start of the hard drive failing? Has anyone heard of any ePub document with malware embedded?