from what you say ... I'd suspect sqb is right ... except same on two computers???
doesn't sound good
http://www.compuapps.com/download/Swissknife/s wissknife.htm
be careful ... but if the drive can be detected this will do it
(it won't recover files ... but it will prove the drive)
if it won't there is a good chance your flash sleeps with the fishes ... an ex flash drive - a flashless drive without a spark
a f@cked flash, a driverless drive, rubbish ram (get the idea?)
I don't know any of these ... but worth a look
http://www.snapfiles.com/freeware/system/fwdat arecovery.HTML