you need the pc version on the computer
The mod developer will need to update the mod to be compatible with the new Minecraft version.
No it might be that you have an out dated mod that crashes to game or that you do not have something like modloader (which you need for most mods). Also when downloading mods make sure they are for your current version of minecraft or it will defiantly crash.
NO!
If by 'full version' you mean a legal copy (you paid for it), then yes you will.
You don't need a CD for mods. You don't need a CD for Minecraft at all.
I believe you need to install Forge first then run Minecraft once before you install any other mods.
any will load mods onto minecraft but the better operating system the more mods you can have
You will need to wait until MinecraftForge is updated to 1.7.2 so that the mods running on Forge can also be updated. In order for Forge to update, you will need to wait until MCP (Minecraft Coders Pack) updates. TLDR; Be patient. :)
In order to play the full version of Minecraft a license must be purchased at the Minecraft homepage. A free, browser-based version of Minecraft called Minecraft Classic is also available on their website but it lacks the majority of features in the full game.
You need the full version
A Minecraft account is 100% free. But buying the full version costs 28.95.
No, to play the full version of Minecraft, you need a premium account which has to be done online.