changing of results of network scan by avast

[jraju]

Hi,
                 On scanning the network scan, ( i use computer and mobile with wifi router), my dns server  was said to be compromised with remote hacking and as a solution, avast recommended the change of dns server to google dns server 8.8.8.8 and 8.8.4.4. I was then using auto detect settings of the router)I scanned again, and it says that it is problem free. Now, as i experienced loss of network, i just changed to auto detect settings , and now the scan says everything ok.
                 My question is how change of results occur one time as infected and next time as Ok. Is it that the time of scan of computer at that time has anything to do with the results.

[jraju]

Hi, My dns server was said to be compromized and i was asked to change to dns google. i changed by chance the same dns server back to the dns server settings in the router , configured by my ISP as i had experienced loss of network connection. The scan in the router settings of default has now produced no error or compromises.So, i raised this query.. I was warned of severe compromize of my dns , that would help hackers to easily remote control my pc. Now the same dns settings produce nil compromises.
              i could not open my router as it was protected with strong password instead of admin as advised by avast in the earlier version scans. The scan was done for computer, my router and samsung mobile. the first and third report no problem. The second, ie, router was said to have compromized with severe remote attack.pl