it is a complimentary hard disk to my 120gb ocz vertex 4(windows installed)
when i plug it in it causes a machine_check_exception error, but when i pull the SATA cable off it would start the windows normally.
sometimes when i cold boot the computer and plug in the SATA cable after the windows started it detected but shown as 128GB disk 2 and unable to do anything with it in the disk management. it says something about I/O error
It may be a faulty drive (even new drives have been known to be faulty, sometimes damaged in transit etc). Contact Seagate about returning it under warranty. They will give you an RMA (Return Merchandise Authorisation).