Paperdoc :
To use all the space on any HDD over 2 TB, it must be Partitioned under the newer GPT system, and not the older MBR system. Since you say that this external unit does work with other computers, but not one particular PC, then then that drive must be Partitioned that way already, and the problem is in the PC.
A HDD with GPT Partitioning is a slightly different device type that an older HDD. So, the Operating System (Windows, I presume) needs to have the correct device driver installed to access that different drive type. If your OS is the 32-bit version of Windows XP, it can't be done. UNLESS - MAYBE Seagate can provide you with a device driver for 32-bit Windows XP that allows access. But if that is not available, you would have to switch to a 64-bit version of Win XP, which is a big change!
HOWEVER, if your OS is a more recent Windows, (Vista or higher), you may be able to get it to work. You need to find a device driver for using a GPT-Partitoned HDD with your version of Windows and install that. This will NOT give you the ability to BOOT from that drive, but you indicate you do not need that ability.
Big thanks for replying as no one is doing it,Le t em tell you in detail so that u can help me better,
I was using i7 3770 with DB75EN chipset intel board ,8gb ddr3 ram,R9290x GFX ,1 256 SSD,2TB HDD,500GB HDD,DVD DRIVE,600W CM THUNDER SMPS
I amusing dual OS One installed in ssd(64bit) and another in hdd(32bit) and OS is Win7 64 bit/32bit Ultimate
It was all working fine when once i got my 2tb seagate backup plus slim got slowed,hanged and then showed error crc and then it don't show up in my computer but it was showing in Device manger and disk management butt not in my computer ,when i tried to format it or from disc management by both gpt/mbr ,it showed crc error ,So i send it for replacement and lost my data,
Then i got a new replacement drive and checked it with other pc and added some file into it,then tried connecting it with the pc and faced the same problem, 1st it showed driver was not successfully installed and then it just don't show in my pc and then same old story,
Then this cycle repeated again with same result,But i tried other seagate 1tb backup plus it worked fine,and other usb drives below 2tb too worked fine, but all the 2 tb or more hdd are failing,Bu the same drive is working with other pc,Even th 2tb internal hdd is also working fine,Totally confused, Checked the SMPS with voltmeter about the current issue but no gain in that,Can i be motherboard but again all other thing and pc works absolutely fine except this continuous issue
Help me to find the fault ,Ask if u need any more information,Thanks