I was opening a PDF on my Acer Aspire 10 tablet when it went black, with just the cursor remaining on screen. I tried ESC, CTRL/ALT/DEL, and powering off. Nothing would work, so I closed the lid and left it for about an hour. Came back and the screen is black, no cursor, and it appears to be dead. Can't start it up. This tablet is not 4 months old, and has barely been used during that time. Suggestions?