Hi,
does your Web-Browser and other internet-applicatiosn work normally ?
how do you access your yahoo-account ?
via Web-Browser, via POP3, or via some external WebMail-Checker like eprompter (which generally doesn't work for a few days since Yahoo obviously changed it's login-procedure)
what WIN do you have ? Are all ServicePacks and Windowsupdates applied ?
WHAT virus (which name) did you delete, and where exactly was it located ?
I.e. where exactly was the infected File found (full path/folder/filename, e.g. c:\Windows\system32\virusfile.exe) ?
see avast's log/reports for this info