Tiger 4.11 to snow leopard 10.6? help what to do before installing new software?

Question

hello,
first time i have asked a question on here so please go easy with me,
basically i have tiger 4.11 and want to upgrade my software to the snow leopard 10.6 so i can use my iphone 4.
my friend has kindly given me the software to upgrade with including serial numbers etc so is it ok to upgrade my computer with this?
also what do i need to do on my computer before i install the new software on mac......do i have to back everything up? if so is there a way of doing this all at once on to my harddrive .... i have a lot of music etc on computer and dont want to lose it?
whats the easiest way of back ing up your itunes?
thanks hope i dont seen to dim in asking these questions
thanks jay

Answer 1

Anytime you perform a major change to your computer you should first make a backup.  Do this as follows:
Repair the Hard Drive and Permissions
Boot from your Tiger Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list.  In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive.  If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes.
If DU reports errors it cannot fix, then you will need Disk Warrior and/or Tech Tool Pro to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.
Next, have an empty external hard drive large enough to store all the files on your internal hard drive.
Clone using Restore Option of Disk Utility
1. Select the destination volume from the left side list.
2. Click on the Restore tab in the DU main window.
3. Check the box labeled Erase destination.
4. Select the destination volume from the left side list and drag it to the Destination entry field.
5. Select the source volume from the left side list and drag it to the Source entry field.
6. Double-check you got it right, then click on the Restore button.
Destination means the external backup drive. Source means the internal startup drive.
Beyond this you have stated you will be installing software including Snow Leopard that has been lent to you by a friend.  Since installing single-user software on more than one CPU at a time is illegal we cannot help you further.