[heero_yuy]

Looks like a Philips rather than a pozidrive. The angles and proportions differ between the two types.

Sometimes these screws have little or no depth to them so a pointed screwdriver bottoms out. Sometimes a well fitting flat blade will get them.

I had a similar issue getting my old Sony lappy apart and eventually resorted to carefully drilling it out. Once the head is off there's no tension and the stub can usually be undone with pliers.