Try putting your XP install disk into your optical drive. If, when you restart you PC (And the boot sequence is correct), you should see the install screen for XP. If you dont - you proberbly have a bad drive.
I run Windows Vista. And there is a boot sequence. I just don't think that Gateway provides firmware or driver updates. Which is a really bad move on their part. And it's not the software. I need help getting the correct firmware.
