This problem almost made me return a brand new 2.5" hard drive to TigerDirect. I installedthe drive in my portable, and tried to install an operating system. However, Windows XP setup failed with the error

An unexpected error (1072) occurred at line 5218 in d:\xpsprtm\base\boot\setup\setup.c.
Press any key to continue.

I also tried to install a copy of MS-DOS, but FDISK failed; or rather, it seemed to have succeeded, but when I checked the disk, there was no partition table on it.

Why? I tried various jumper settings (cable select vs. primary) to no effect. I checked Google, but couldn't find anything useful either. I looked at my BIOS... and that's where, eventually, it hit my eye: I had the setting that protects the boot sector from accidental (or malicious) overwrite was ON. I turned it off, and presto: everything worked well afterwards.