alarmabg

Hi friends, I have a very big problem with these models of Dahua, they stop working after 2-3 years, something like virus goes in trough telnet probably and after that everythyng goes wrong. The DVR does not wants to start, I can't see it online or by HDMI on a monitor. Do somebody have messed with this problem and if do, is thera a chance to fix it? Thanks in advance!