You’ve got a formatted drive that contains data, yet when trying to access the data from another computer, you get “Disk is not formatted” error. More importantly, in this case, it appears as 138GB when you know its larger. This means your OS and/or mobo is set to support 28-bit Logic Block Addressing, instead of the modern 48-bit LBA.
I’ll bet your on XP SP1 or earlier. Patch up to atleast SP2. Patches are available for 2000 and 98 too. Also, use manufacturer updates to the mobo chipset, too. done