It's easy in any of the later OS. In XP or W2K, you can change drive letter and path in Disk Management. In W2K or XP(using the classic interface), right click My Computer > Manage > Disk Management > right click the drive > Change Drive Letter and Path > follow the prompts. If other drives are using the desired letter, you will need to reallocate the drive letters for the effected drives first. You cannot change the drive letter of the boot or system drive, since Windows does not support this method.