Hello,
Recently I've bought a new pc with the following stats:
Processor: AMD Phenom II X4 965 
Mainboard: Gigabyte 790FXTA-UD5
Graphics card: ATI Radeon HD 4850 X2
I've been running on an old HDD and I wanted to upgrade to SSD. After a lot of hassle at the installing progress, I've managed to install W7 on the SSD. My problem is that I can only run the SSD in SATA2 slots. When I simply connect the SSD to SATA3 it will not be detected and Windows keeps rebooting (I've still got my old HDD with windows installed in a SATA2 slot.) 
The SSD I bought is: PNY, it shows in Windows as: SSD2SC120GC1DH16T2-T ATA Device.
I have the following questions: 
Is it essential to have a SSD connected to SATA3, and will it run 'slower' on SATA2?
How should I connect it with SATA3? 
Why does windows not see my SSD? 
How can I solve my problem?
Thank you for your time reading this.