Need help restoring iMac

[M-5]

So my mom just bought an iMac from her friend's mother, and I'm trying to restore it to factory settings using the Installation disks that came with my MacBook Pro. I just inserted the discs and clicked "Install Mac OS X" and then it gives me a "Restart" button, but I cannot restart it without putting in the Password which I do not have.

Is there another way to do this?

 

[M-5]

So I reset the password by restarting the computer and leaving "c" pressed while it booted up. But now when I clicked the "Restart" button after inserting in the disc to restore it says "Mac OS X cannot be installed on this computer" after it resets. Is it because it's not the CD that came with this computer?

 

[drir1990]

The installation disks are model specific.

 

[mysterytramp]

How old's the iMac? Your mom might be better off -- as painful as it may be -- for her to use OS 9.

mt

 

[M-5]

Well I believe the Mac is about 2 years old. But it's in really good condition. It was really dirty, but I managed to clean it all up.

Aluminum 20" iMac
2 GHz Intel Core 2 Duo
1 GB Memory 667 MHz DDR2 SDRAM
Build 9A3129
226.88 GB Hard Drive Capacity

Yes it's a little bit old, but she bought it for $500, and didn't really want to shell out the money for a brand new one. She only uses the computer for the occasional internet and spreadsheets, so it should do her great.

I contacted the previous owner for the installation disks, but I doubt they still have them.