Have tried, I think, all possibilities...
Seems the DNS are controlled by the provider, no way to change them in the modem.
Have changed DNS in my PC, I can go in internet, open OpenDNS page, login, open my modem page, but cannot find the way to change the DNS of the modem. (Of course, still cannot open AVAST nor Microsoft pages).
Have seen the DNS in both PC and netbook are the same. What changes is the IP.
Have also noticed , each time I clean the disk (each time I go out from internet), even If I have opened one or no page, there are a big quantity of files to compress (

), round 27MB(!!!).
Today I have called again the provider and talked with a technician. He said they cannot change the DNS (!!!), they can only read it.... I asked which were those values and he gave me (for the ethernet connection) 2 very different ones [from the DNS I can see on the control panel (IP link) of my modem], and didn't want to give me the link where he could see those DNS values (said was a private info)...
Someone blocked the connection (!) (= cleared the sftw. to reach the modem) and I had to erase the connection program and reload it newly (from provider's CD).
Please HELP!
Have just controlled the clock of my PC: it was 8 days and some minutes back (!!!!)...