hey i have this mac and it wont let me update it or itunes i check for updates and it says its up to date but its not what should i do?

Can you post this sort of information for your Mac? or year and Mac Pro 4,1 or similar?

-menu > About this Mac

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That appears to say you have a PowerPC G3, running 10.5.8.

That is already the last version of Mac OS X that processor can run. To get a newer version of Mac OS X, you will need a newer computer.

These computers will continue to run the programs they were built for as long as they keep operating. But the last PowerPC computers from Apple were discontinued in August 2006.

You are looking to add features invented long after the PowerPCs were discontinued. That will take a newer computer.