I have two SAT HDD-s ones a 500 gb, the other is 1tb. I installed windows 7 32 bit on the 500 gig, made a new partition and installed windows 7 64 bit on the same HDD and left the 1tb for general use. After two days of use, the 1 TB HDD showed two out of four volumes available. Luckily, i didn't have much on the 1TB HDD. I formatted it and took advice from a friend of mine to install the 64 bit on the 1TB HDD. It worked well for a week and then the 64 bit wasn't starting up anymore. So i reinstalled it, both operating systems were working well, but the problem of the missing volumes still continued in the 1TB HDD. I thought maybe the 1tb HDD was faulty, but it wasn't the case. It works fine, there are no bad sectors. I need help as to what I should do next. My hardware configuration is as follows- computer type - desktop pc HDD- 1tb and 500 GB samsung SATA RAM- 8 GB DDR3 Processor - intel core i7 quad core Motherboard - Intel dh55tc thanks in advance.