W32: trojan:gen {others} infecting ms0920b.dll

[fzvgw1]

 I actually have a problem and being infected by a trojan " W32: trojan:gen {others} . This is picked up by Avast  but when I delete the infected file "ms0920b.dll from the
..|windows\system32\   then 3 applications ie acrobat , juste.exe, rschedule.exe and sound.exe got affected for not findind the dll file.

Do you have any suggestion? Most appreciated if you can help.

[DavidR]

What OS are you using?
What avast! version and VPS file (virus database) number, e.g. 0520-4 (see about avast!)
What was the virus name (for the other 3), what was the filename, where was it found (for the other 3)
  example (C:\windows\system32\infected-filename.xxx)?
What actions have you taken to try and resolve the problem?

If you have XP you can schedule a boot-time scan from within avast.

Also see - Advice & Tools for virus/trojan/malware Removal & Prevention