I have an infected computer, can Avast! clean it?

I have an Avast! product on one of my computers. My sister didnot and has a serious virus infection. Can I install Avast! on her computer and clean the infections?

it depends what malware you have…

so i suggest you start with this, and post the logs so our malware removal expert can have a look

Follow this guide from our expert malware remover Essexboy
http://forum.avast.com/index.php?topic=53253.0
( post the logs here in this topic and not in the guide )

To avoid using multiple post with copy and paste you have to attach the log`s
Lower left corner: Additional Options > Attach ( Malwarebytes log / OTS log ) save OTS log as ANSI

Essexboy will look at the logs when posted…