There Isn't Enough Information In Your Question To Answer It Properly, But Uninstalling And Re-downloading Usually Works.
Xp is a PC, so yes.
In Portal 2, you can shoot a portal on any surface that is designated as portal-compatible, typically marked by a white, smooth texture. To shoot a portal, simply equip your portal gun and aim at the desired surface. Press the left mouse button to place a blue portal and the right mouse button for an orange portal. Make sure to look for surfaces that are specifically designed for portal placement, as not all surfaces will work.
Yes, the Spyro's Adventure Portal will work on Giants. So you can buy the Portal Owners Pack.
Portal or Portal 2 mods on Steam is installed by first Downloading it and extracting it. Then copy the map file into your Portal 2 maps folder which is Run the game.
Yes and Portal 2.
No, Portal is for PC only. Portal 2 is for PS3,Xbox 360,and PC. Plus it would suck on PSP.
Portal - 2002 Portal 2-21 was released on: USA: 18 November 2003
Portal 2
no. it wont work
Portal 2 comes out on April 18, 2011.
It will be on Mac the day Portal 2 is released.
Wait for Portal 2.