Vlk, one of my computers has the same problem.
Maxthon + avast give me some ‘blank’ Internet pages.
Sometimes I solve the problem with the command:
C:\Windows\system32\ipconfig.exe /flushdns
Sometimes, opening and closing the browser.
Sometimes, booting…
It’s weird that just one of my computers acts this way. I could not found the final solution yet. I did not try ‘disabling’ avast and I’m not sure (of course) both things (the problem and avast) are related :-\ :-[