NEC 3500 Removable Device?!

I recently bought the NEC 3500 and I upgraded the firmaware to 2C8 without any problems (great burns). Then the drive would occasionally not be recognized by windows (have XP Pro SP1) - but a restart would usually fix that. Now it has progressed to the drive only being recognized as a removable drive. Anyone experience this or hear about this? Since the drive isn’t recognized I can’t flash it. Hope somebody can help me out. Thank you in advance.