my old iphone 3g disabledhow can i unlock i forgot passcode

Erase and reset it, and set a new passcode:

If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

gatofelix71 wrote:

if i coonnect it to my last backed up coputer is it possible to un disable phone

When the passcode is forgotten, you can only reset and reload the iPhone.

Again, your only option is reset and reload.

Without the contents, you cannot decrypt and access the contents.

And if the buttons are (also) failing, it’s type to recycle this iPhone 3g.

Click here and read > If your iPhone, iPad, or iPod touch won't turn on or is frozen - Apple Support

gatofelix71 wrote:

need photos dont want to lose data on it

They’re already gone.

With no local backups and no iCloud backup and no iCloud photos, and no passcode, this is little different from a lost or damaged or stolen iPhone.

That passcode is the encryption key to the iPhone contents.

gatofelix71 wrote:

my power off button not workking

if the following doesn’t work, and without the passcode, it’s time to recycle that iPhone 3g. It’s not worth fixing...

If your iPhone, iPad, or iPod touch won't turn on or is frozen - Apple Support

when the phone is disabled, it's too late to recover content from it