big problem please help

the thing is…ive been using avast for more than two years and ive never had problems with it.works great all the time.but last week i noticed that my resident scanner doesnt work without doing any settings.its disabled right now and i can`t enable it.please people help me i would really appreciate that

Hi ivan.kirchev@abv.bg

Could well be that some malcode tampered with your hosts file. Well do a full scan with MBAM, download from here: http://www.malwarebytes.org/mbam-download.php (first update to the latest version).
Also download HJT 2.0.2 from here: http://www.filehippo.com/download_hijackthis/download/58170ee6e58bba306c943f5b6d745c99/ and provide us with a logfile txt attached as an additional txt file to your next posting, then we can have a look,

polonus