I think the hardrive died on me... (Can anyone help confirm)

Question

I think the Hardrive (80Gb) in my 17inch G4 1,5Ghz powerbook died on me.
When I try to restart it doesn´t go beyond the grey screen, then it shuts off again. There is no sound of the disk starting up either.
And when I start it from the OSX Start-up DVD and try to reinstall the OS, It doesn´t locate any disk to install to.
Just before this happened, a game that I play frequently (Medal of Honor: Breakthrough) failed to start because it couldn´t locate some files, also the disc utility would take forever to verify the disk, but when it finally finished it claimed it to be ok.
Luckily I decided to back up all my personal data, when I got the above symptoms, so all my stuff is savfe on dvds.
1) Now before I purchase a new harddrive, is there anything else I should try first?
2) And secondly, when I buy a new harddrive can I buy a larger one than the 80Gb that came with the powerbook (Will the internal stuff support it?)
3) What is the appropriate type of drives that will fit (This I will probably find on google, but since I am here I am throwing it in...)
Thanks in advance!
G5 Dual 2 GhZ (first release)   Mac OS X (10.4.8)  

Answer 1

1) Now before I purchase a new harddrive, is there anything else I should try
first?
Can you use disk utility (boot from startup CD/DVD) ? What does it state about the harddrive ?
2) And secondly, when I buy a new harddrive can I buy a larger one than the
80Gb that came with the powerbook (Will the internal stuff support it?)
Yes, this should be no problem. Look at http://www.ifixit.com (or any other website) for DIY guides of how to replace the harddisk and also find some offers for harddisks suited to your computer.
3) What is the appropriate type of drives that will fit
All 2.5 inch ATA/IDE drives.