MiCRoPhoBIC: I believe you did somehow broke something in your tablet... It seem that the tablet does boot up properly since you can see it from your PC. If it was not booting up it will not show up as USB device.

EDIT: You said it comes and goes as USB drive? This may be caused by a "reboot loop", but since you were able to flash it successfully this problem should have gone away. Unless there is some watchdog that reboots the tablet after certain time period due to malfunctioning hardware...

You may want to open it to check if you can find loose connector or broken cable etc... This link has all the documents you need how to open the tablet. (And troubleshoot it further if you have the electronics skills and equipment... )
http://www.internettablettalk.com/fo...d.php?p=249264