i want to find the new features and release notes of every avast version .how do i do that?
is this what you are looking for? http://filehippo.com/download_avast_antivirus/changelog/
on the right side you see all versions, and if you click one there is a " change log " tab…
well thanks for helping me out. This is exactly what i was looking out for
fine 
now i would like to know how to mark a topic as resolved?
in top rigt side inside one of your post`s you will find a " Modify " click it and you can edit the topic name…
if you click the button under it, you can only do minor/quick edit
didnt quite understand what u said. I dont want to modify or edit the topic . Since i am finished with my problem i want to mark the post solved. That’s all! how can i do that?
Pondus was correct, but maybe not clear enough for you. You do want to Modify your first post, which started this thread, and all you need edit is the subject-title.
Click on the Modify button to the right of your first post in the topic. Once the modify screen opens, add [Resolved] or [Solved] at either the start or end of the Title of the topic. As I have done for this post.