Can Not Reboot Matrix Tablet

[jiidii]

i bought a matrix 7" tablet using google 2.1 android o/s and i recalibrated it and now i can not reboot it, i have tried the reset and all i get is and android logo trying to reboot but nothing happens, i have tired holding down the on/off button to turn it off and it will not turn off, i am not very experience with these and have run out of ideas on how to reboot this, i would appreciate any help i can get