Default A little help plz

My i9003 has problems with connecting to PC. Drivers are latest v1.5.33.0
It connects & dissconnects automatically.. now its not connecting anymore..
It was on froyo & I flashed GB on it.. since then problem.
Also usb debugging is on & in wireless settings - usb - it says to turn off usb debugging!!

Suggest something as I wanna try cm11 on it

Thanks in advance

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Phones: Samsung Galaxy S III (GT-i9300)
Samsung Galaxy Mini (GT-S5570)