|Doesn't matter if you have a network or not. The boot order has that option included so the computer tries to boot from it.|
Watch the POST screens at start up to see if the hard drive is being configured by the BIOS. If not, then either the drive is dead or less likely, the cabling is loose.
If you didn't make the restore disks while the drive was operational you will need to purchase a hard drive and a set of restore disks for Gateway. Assuming they are still available. If not, you will need to either borrow a restore set from someone with the same or very similar Gateway computer to get yours working again. Other option is to buy a full version of Windows that is compatible with your computer.