Verbatium 150GB external hard drive intermittant operation

I recently purchased an external hard drive (Verbatium 150GB) that has intermittant success being recognized. Probably 75% of the time the blue power light flashes, when this happens my computer will not recognize it at all. Occassionaly the blue light stays on steady, at that time it is recognized by my computer and works fine. I cannot find any other on/off, reset, etc buttons on the unit, so the only thing I can do is plug it into a USB port and hope for the best. I have not been able to use it for approximately 2 weeks. Rebooting the computer nor logging on/off seems to have any effect on the unit. I appreciate any help!