First you need a Sega Dreamcast Emulator (For original Sonic Adventure) or a Gamecube Emulator (For Sonic Adventure DX, which is an upgrade of the original). After that you need to download the emulator AND the ROM for the game you want to play. Note that the emulators are not Nintendo/Sega approved or licensed.
Yes, Sonic CD, Sonic Mega Collection Plus, Sonic Gems, Sonic Heroes, Sonic Adventure DX and Sonic Riders are all playable on PC.
There is no such thing as Sonic Adventure Battle 1, nonetheless no Sonic Adventure is playable on Sonic Mega Collection.
But you can play metal sonic.
You can't play as Silver in Sonic Adventure or Dx, Silver wasn't thought of until Sonic the Hedgehog 2006, Play Sonic the Hedgehog 2006 to play as Silver.
The only two games that allows you to play Eggman is Sonic Chronicles: The dark brotherhood and Sonic Adventure 2 / Sonic Adventure 2 Battle.
No.
No its not
you can only play as super sonic when you fight the finalhazard.
sonic2online.com
You don't because unless you already own a copy of the game, it's illegal.
Metal Sonic doesn't get a story in Sonic Adventure however you can play him in trial mode to unlock him get all the emblems you can go to every level Sonic goes to as Metal Sonic you can even fight the bosses and play the minigames.
she is not playable