F-Secure Anti-Virus had a relatively common false alarm with this virus in March 2001. This false alarm caused FSAV to report the Opera virus in several different VxD files.
If you find Opera in a file with vxd extension, simply download the latest updates for your F-Secure Anti-Virus to fix this false alarm.
Opera is a DOS-based virus. Two varianst are currently known. It is resident, non-encrypted, non-polymorphic. Infects COM and VXD files using prepending infection method. The virus can be removed using F-Secure Anti-Virus.