I'm now using a sata harddisk on my motherboard. i'm not sure if now i were to buy a sataII harddisk, can it be used on my motherboard? what do i have to look out for?
You need to look for the SATA transfer speed of your board. If it supports 3GB'sd/sec. then use SATA 2. Either SATA drive is plenty fast.
Yes, it is backwards compatible so the new SATA drive will work but at the slower speed of the SATA 1 drive.