i have a similar problem with my seagate 500g hdd. use it as slave and every now and then it just disappears from explorer until reboot. when all the issues with these drives was going on, i checked to see if mine was one of those affected and it was not. i also use it as my default download drive and occasionaly my download aborts , because it can't find the drive. running win7 ult 32bit.
You probably looked at the wrong list like many other people. What is the model & serial number?