Windows Vista [Corrupt driver error message on boot]

My emachine computer is saying a driver is corrupted and I am trying to do a total reinstall of windows vista but when I insert the disk and it pulls up the screen needed it won't go past the press Y to confirm you want to do it because it says I need to change the stack number in the config.sys menu. I don't know how to, or if I can even, get there because my screen goes straight to the driver corrupt when I power it up. Can anyone help me?