Hi there. My pc shows me that the file RVHOST.EXE has been infected by a virus, when I try to scan, my antivirus cannot see anything. But up to so far I cannot access the registry editor and everytime I switch it on it shows me that the RVHOST.EXE is missing.

May you please help me on how to remove this malware?

Perhaps a search on this site (or others) would lead to a list of possible solutions, like so:

http://www.askmehelpdesk.com/spyware-viruses-etc/how-remove-rvhost-exe-malware-71164.html

Download super anti spyware and use it this will tale care if the malware and for the regestry editor try cceaner. if you have any outher problems after removing the malware with super anty spyware e-mail me and i`ll see what i can do.
Good Luck
Download super anti spyware at SUPERAntiSpyware.com - AntiAdware, AntiSpyware, AntiMalware! (http://www.superantispyware.com/)

First create a restore point before scanning your computer,It is virus. please end the process from windows task manager for rvhost.exe and scan with Smithfraudfix in safe mode.then scan your computer through Malwarebyte in normal mode.