Bold 9000 Problem

[nonferrous]

Please help, I've bought a new bold 9000 from ebay it had o/s 5 on it but would not connect to pc via usb and on desktop 6 it would not synce to media,
I came on the forum and downloaded another o/s from a link and now I have o/s 4 and cannot upgrade. I have another bold which is on o/s 5 and works fine. how can I get this new one the same as the other one ?

[saudadeii]

Go to the Blackberry Help section using the button at the top of the forum. You'll find detailed instructions on how to install the OS.