Hi, Welcome to the forum
So, from the looks of it, your Touchpad one day just went cold, no signs of life...
Sometimes that may happen when the OS kernel crashes while the Touchpad is "sleeping", but since you've tried all button combinations, i guess we can rule that out
When the battery gets over-discharged from disuse, it can also look "dead" and not charge from any power source over 500mA (computer or printer USB port). But you've tried charging from your computer, so we can rule that out as well because the Home button doesn't flash, though you could try for another two days
Another possibility may be corrupted A6 firmware or the Touchpad being stuck in QHUSB-DLOAD mode, which can both be fixed if we can get your computer to somehow see the Touchpad.
The last option is to open it up and pop out the battery for a few minutes, to see if that would correct the problem. Otherwise, there may be an interrupted circuit inside and you'd have to mail it to one of the guys here who still do repairs.