I recently bought an Imac from a friend and it didnt come with any disks, I think I need to do a full format so im guessing i would need to buy the disks to do that.
You can your coming from Windows. I wouldn't bother. There isn't a massive invasions of malware on the Mac platform.
I would buy a backup hd. I'd call OWC for a backup hd.
I'd give OWC a call. 1-815-338-8685.
FireWire 800 + USB 3, + eSATA
save a little money interface:
FireWire 400 + USB 2.0
This web page lists both external harddrive types. You may need to scroll to the right to see both.
(2) FireWire 800/400 Ports (Up to 100MB/s / 50MB/s)
(1) USB 3.0 Port (Up to 500MB/s / 60MB/s)
(1) eSATA Port (Up to 300MB/s)
Has a combo firewire 800/400 port. Not sure what this is. Looks like you will need 400 cable.
Restore DVDs are available from Apple by calling 800-767-2775. Have your serial number ready. Have your credit card ready too. There is a small fee.