test it as an internal in a desktop system...use the Seatools, Data Lifeguard, PowerMax or whatever diags are applicable to this drive. If it tests OK after repeated testing..I'd write ZEROs to it or wipe and start over. Might even partition and format the drive before putting it back in the external enclosure. If it acts up thereafter...got to believe there's a problem with that.
I'm using a 3200AMD, 1GB memory, Win200pro, SOYO M.B
I installed a 120GB WD 7200 drive in an external USB 2.0 fan equipped housing. This is the second case it has been installed in, with identical trouble in both cases. Most of the time, when booting, it will go as far as the memory check, and freezes with ''memor'' showing. Turn it off, restart the boot, and all goes fine so long as that drive is turned off. When it is turned on after boot, the drive starts up OK, but it will blink for a bit, then the red search indicator shuts off and the indicator stays green. Checking the USB 2.0 in Computer management shows the yellow warning. Uninstall the usb from this drive, and then it will recognize the drive, and it will install. I have 3 other USB hard drives on the same bus that never give a minutes trouble. It is not the hub I use, nor is it a defective USB cable. Partitioning and formatting the drive does not stop it from doing the same thing on the next boot. It does the same thing whether the other drives are hooked up or if they are turned off. After it is recognized, the format is still there, and it accepts and/or transfers data ths same as the other drives, but it will usually repeat the lost access on the next boot. It does the same thing when hooked up to my wife's laptop. The other case now contains one of the 3 other drives and it causes no problems. This drive takes a fast format, but will not take a regular complete format in any partition setup, even after running for a couple of hours.