Resident Protection

[sameer]

Actually I don't understand the function of resident scanner. Is it only to protect invasion of virus or deletes virus simulataneously?

[Eddy]

Resident in this case means "always there". So the scanner is in memory and running all the time. Which is good. How else could it alert you when something harmfull is found?

Is it only to protect invasion of virus or deletes virus simulataneously?

Basicly, neither of them. The scanner is running. With Avast, as well as many (all?) other av applications it is a on-access scanner. This means that if a file is accessed one way or another it will be scanned and the av software will alert you when something harmfull is found. When the application is giving you the alert it is up to you to decide what to do. Unless you have set it to "automaticly delete" "ignore" or whatever setting you have chosen.

[sameer]

My free avast home edition does not shows automatically remove or delete on the appearence of alert message. what should i do?

[Eddy]

That's correct. The home version is limited in its options, but there is something like "silent mode" (can't recall what it is named exactly) which you can set.

[Lisandro]

My free avast home edition does not shows automatically remove or delete on the appearence of alert message. what should i do?

Home version, like Eddy said, can only 'Send file to Chest' on 'Silent Mode' and general (default) answer 'No'.
Professional version has a fully automated action when a virus is found.