Hi crinklecut,
If possible, give more infos about your hardware configuration.
CPU, PSU, video cards, Hard Disk, SSD, etc (Add a weblink for HD and SSD, please)
What is your BIOS version?
What is your exactly Window version.
Have you a SP1. Service Pack One. If no, install it now before anything.In waiting time, just verify if you have installed a:
Have you installed a IRST : Intel® Rapid Storage Technology ?
IF no First Install it:
http://downloadcenter.intel.com/SearchResult.aspx?lang=eng&ProductFamily=Chipsets&ProductLine=Chipset+Software&ProductProduct=Intel%C2%AE+Rapid+Storage+TechnologySecond
3TB+ Unlock Preinstall driver(Note) Support Intel X79/Z68/X58/P67/H67 series and AMD 900/800 series MB.
(Note) Press F6 during Windows setup to read from floppy.
(Note) After installing the operating system, if your system keeps rebooting automatically, refer to the following recommended solutions.
1. Recover your Windows operating system with the Automated System Recovery function. Boot from the Windows Setup disk. When prompted with the message "Press F2 to run Automated System Recovery (ASR)", press F2 to run ASR.
2. Connect your hard drive to another SATA port.
Third :
3TB+ unlock(Note) Support Intel X79/Z68/X58/P67/H67 series and AMD 900/800 series MB.
(Note)
Please install 3TB+ Unlock Preinstall driver first before running 3TB+ Unlock utility.You find this utilities in :
http://www.gigabyte.com/products/product-page.aspx?pid=3761#utility=============
You have a possibility to view by Administrative Tools (Starting Menu), in Window's Disk Management program, if by right click on the 3T drive, this drive is in One part or multiple part. Like with a one partition of 2Tb and other of 1Tb. (Grey or not Grey).
If you have a data on this 3T disk, Save it before continue modification with Window's Disk Management program.
Try to see if you want all erase 3TB disk and partitions. After it, make a new only one partition, if you want it.
Source :
http://windows.microsoft.com/en-US/windows7/Create-and-format-a-hard-disk-partitionOtherwise, choose if you keep 2Tb partition and by right click on this, in contextual menu, choose Convert to GPT.
Help here:
http://seagate.custkb.com/seagate/crm/selfservice/search.jsp?DocId=218619&NewLang=enSo come back here, for comments. Take a courage and patience.
Gloup_Gloup