Each time the computer start up, warning appear windows annot find the rvhost.exe.
What type of virus is this. How to remove it. Now I'm using avira and can't detect it

Since questions concerning rvhost.exe have come up many times on this site, the first thing that I would suggest doing is typing in rvhost.exe in the search box at the top of this page and taking a look at the questions and answers that are on many threads on this site.

You can also find them similar questions at the bottom of this page "Similar Questions";)