This could be for one of two reasons.
1. The guitar is not synced so you might need to sync it.
2. If the guitar is synced, the batteries are about dead and need to be replaced.
If it's a wireless controller, the blinking means you will need to charge it/replace the batteries soon.
Guitar Hero World Tour and Guitar Hero Metallica
No, you can use the guitar hero 3 controller, which is wireless, for guitar hero two
Insert another Guitar Hero controller, The Guitar Hero Controller if you are playing with a system controller, or your system controller if you have a Guitar Hero controller. I use a Fender Cream Strat when I'm using Guitar Hero for my PlayStation 2. That is because my piano teacher, Rick loves Fender Strats.
That completely depends. Is the guitar hero 3 controller for the same platform as the guitar hero 2 controller ? (I.e. xbox 360 or ps2)
Yes, Guitar Hero 2 controller will work in any other guitar hero game same as guitar hero world tour controller can work on any guitar hero game, But you cant use xbox360 controller on another console guitar hero game.
no
yeah it will but you can't tap with the guitar controller on guitar hero two.
haven't played guitar hero in years but for PS3 I know it was the Ls and Rs with one button on the face of the controller. That was the case for guitar hero 3
yes
Yes.
Yes
yes