|We can probably help you better if you supply the model number of your Gateway computer - it's probably on a label on the outside of the case.|
As far as I know the Seagate Barracuda models are 3.5" only - so you must have a desktop computer and not a laptop.
Are there now two hard drives connected and recognized by the bios on the computer, or just the new one?
The new hard drive has no data on it, and because of that it has no operating system and it's not recognized as bootable by the computer's bios yet.
You have to boot from the Gateway CD, but .....
Your single Gateway restore disk can only be used with the original hard drive along with the original data contents of the second partition on the original hard drive.
The original hard drive on brand name system computers always has a second partition that contains the data necessary to restore the original data on the much larger first partition - C.
Sometimes you can see that second partition in Windows but you're not allowed to access it, or the second partition is hidden so you can't see it in Windows, depending on what the brand name intended.
If you want to install the original Gateway software on the new hard drive......
- if you still have the original hard drive, that hard drive works fine, and it still has it's original data on it and Windows works fine, you can connect your original drive and......
.... also connect the new drive , and download MaxBlast from the Seagate site and install it on the original drive, and use MaxBlast to copy the existing data contents of the whole original drive to the new drive - use the Manual method so the new hard drive has two partitions that fill the drive and the second partition is the same size it is now. I can explain more if you need more info.
use the Gateway supplied program on the original hard drive to make the Restore disk set for your model, then you use that set to load the new hard drive with the original Gateway software.
If there is no such Gateway program, or if the original hard drive, or Windows on the original hard drive, is no longer working properly, or if it's data has been deleted, you may be able to order a set of Restore disks from the Gateway site for your exact model, and use that set to load the new hard drive with the original Gateway software.
If Gateway doesn't have the Restore disk set, you could search for one for your model on the web and buy one from them, and use that set to load the new hard drive with the original Gateway software.