install laptop SATA2 Hard Disk into a PC desktop as an internal HD

hi

Is it possible to install laptop 2.5" SATA2 Hard Disk into a PC desktop as a just one internal HD?
Do I get problems with a sleep, hibernate mode?

To install a 2.5" drive into a 3.5" drive bay, you need a mount kit like this one: http://www.newegg.com/Product/Product.aspx?Item=N82E16811993005
There won’t be any issues that I can think of, as the only difference between a 3.5" and a 2.5" drive is its size and a different power connector, which can be overcome by using a mount kit.

THX a lot!

BTW Do I get lower speed (transfer) with 2.5" drive instead of a 3.5"?

The transfer speed will be the same, because it uses the same connection type.