D915GAV and SATA 2.0

I have Intel D915GAV motherboard. I want to ask if it supports SATA 2.0 hard disks.

Earlier I had a SATA 1.0 hard disk, but it got bad. I then bought SATA 2.0 hard disk. But, on connecting to the PC, it starts to behave like its getting stuck, or is going bad. I thought the new hard disk was bad too, and I got it replaced. But, the new replaced hard disk too behaved the same way. I ran Seagate hard disk check, and it failed.

I then checked the hard disk on my cousin's PC, which is quite a new system. On that PC, the hard disk works fine, and it even passes the Seagate hard disk check. So, the problem is with my PC somewhere.

I have read that SATA disks are backward compatible, and so, my motherboard should be able to support it. Then why does the hard disk not work on my system.

I posted this issue on Intel Community, but haven't got any answer there.