Throwing on the mac...

[jtr]

I assume since you are able to play Amnesia on your Mac, it is a recent one, and those usually come with a Mighty Mouse by Apple. If that is the case, it has two buttons, but they are both assigned to primary mouse button by default. You can reassign the right button to "secondary button" a.k.a. right-click in the System preferences.

yeah but the problem is you can't really click right while holding left, i don't mind mac pc's but their mouses are so bad.

indeed they are.. anyhow, I didnt know that, since the only macs I use are those at work, and I dont play Amnesia there for obvious reasons.