My iPhone 3g 2.0.2 is having problems,

[EAG8999]

My 3g 2.0.2's ipod will not work...I can look through my songs and even press play and it will say it is playing but no sound, not even with the headphones...😕...and on top of that half of my downloaded apps will not work...😡...I got the phone yesterday and it was working fine until a couple of hours ago...some apps that were previously working will not work after I downloaded 10 or so new apps...neither will the new ones... after I press the app it will go to its entry screen or a black scree then go back to the home page ...😕...How do I fix this problem, or will I have to restore the phone...I'd appreciate any educated responses! Thanks...