I had the same problem with my Gateway a while ago. I just popped in the Recovery CD that came with my system and reinstalled the OS. Maybe give that a try.
I believe with mine there was an option to format the HD before it reinstalled the OS and an option to NOT format the HD before it reinstalled the OS. Make sure you choose NOT to format the HD if you don't want to lose any of your data.
If you can't access your CD to reinstall the OS make sure to go into your bios and verify that you are booting from your CD rom in the boot order. I think the default boot order is A: then C:. You might need to change it to D: then C:.
I'm not all that technical but that's what I had to do when I had the same problem. Good luck!!
I believe with mine there was an option to format the HD before it reinstalled the OS and an option to NOT format the HD before it reinstalled the OS. Make sure you choose NOT to format the HD if you don't want to lose any of your data.
If you can't access your CD to reinstall the OS make sure to go into your bios and verify that you are booting from your CD rom in the boot order. I think the default boot order is A: then C:. You might need to change it to D: then C:.
I'm not all that technical but that's what I had to do when I had the same problem. Good luck!!