Connection failed every some hour

hi,
i live in austria and i have a chello connection about one month.they give me the modem arris cornerstone cm 200.my problem is that every hour or every some hour,day or night my connection failed and i cant acess the internet.i have to make restart and then works again.they give me a new modem the arris touchstone cm 450b,because they say this is maybe the problem.i make format on my win xp but is again the same problem.when i push repair it says renewing the ip adress failed.please help

I think it's better you call your helpdesk. Because they can help your better with this problem.
It seems like there's someting with your (cable)connection

And please turn of your caps lock :<>

Check properties of your nic and turn power saving options off. They will make your nic to reconnect to the cable network. It might help

I think its your nic, it looks like it is badly installed. It also could be the cable to your modem.