Note the word "usually".
Your best bet is to test hard drive to see, if it's really dead.
If it's not, we can try some other steps to solve your problems, before we go for a new drive.
As for reinstallation, most likely, you have two options:
- use Gateway recovery partition, or recovery DVDs to restore the computer to its original state (in this case all drivers will be in place, along with all Gateway pre-installed crap)
- use Vista DVD to perform clean install (in this case, all Gateway pre-installed crap won't be there, but you MAY need some drivers)
In both cases, all your data will be gone.