I agree. Your first step should be to check out the Cisco website for your correct IOS. Remember that Ram and the Modules installed (fibre, Wic etc etc)all have to be accepted by the IOS. The web site will tell you. Also, try not to download any TEST IOS upgrades. As these are not guranteed to do thier job 100%, unless your router or infrastructure calls for it. I have had my fingers burned in the past! Hope this helps!