There are a type of screw with round hole instead of a cross. How do I open a casing with such screw?

There are also screw (cross) that are so tight that I damaged it when I turn it (yet still can't loosen it). Now I can't use screw driver to turn it. Any idea how to open it?

I believe the round hole ones are not meant to be opened. They are usually welding inside your casing.

As for the broken screw... hmmm... a bigger size one might do the trick. Either that, you can try to freeze the screw so that is easier to remove.

if u pos tthe pic here sure lot easier....

i think tats a rivet lar..
if u relly have to open a rivet, just use a drill. its aluminium so easy to drill.

if u r sure it is really a screw, then use a saw and make a cut accross, then use flat blade to open.

About the very tight screw...when using a screw driver, use a playar(don't know whether spelling right or not) to grip the screw driver and turn the playar. The further the force from the center the more the torque.

hammer can ar??

surely a rivet because only rivet has a round starange shape except the push pins?