HT1338: OS X: Updating OS X and Mac App Store appsLearn about OS X: Updating OS X and Mac App Store apps
Currently Being ModeratedApr 8, 2013 7:55 PM (in response to waasman)
Yes. But before you do that I would do the following:
Repair the Hard Drive and Permissions
Boot from your Snow Leopard 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, then quit DU and return to the installer.
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.
Now, make a backup of your hard drive. Then boot from the Snow Leopard installer DVD and upgrade.
Currently Being ModeratedApr 9, 2013 4:30 AM (in response to waasman)
can I load the snow leopard os over my existing os and not lose pictures or songs
Yes if your already on OS X Snow Leopard 10.6
See #8 Reinstall Just OS X + Software Update
However you should backup files REGARDLESS as anything can happen at anytime.
Yes if your upgrading 10.4/10.5 to Snow Leopard 10.6
However if your hard drive is more than 50% full, then it might be slow. Move just your users files temporarily to a external storage drive (not TimeMachine) and reboot, check in Activity Monitor than you have reclaimed drive space, then upgrade to 10.6, then reboot and Software Update to 10.6.8, then return your users files into their respective Music, Pictures, Documents etc., folders.
If you have problems upgrading to 10.6
Optional: For Snow Leopard Speed Freaks
I do NOT advise you upgrade to 10.7 or later on 10.4/10.5 issued hardware due to risks and performance issues, your PPC based programs will not work and require replacement.