This is not a virus but a Windows-based trojan horse.
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First check if your F-Secure security program is using the latest detection database updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
NOTE If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note You need administrative rights to change the settings.
There are two variants of the backdoor. They have been circulated in email and newsgroups postings as attachment files called PICTURE.EXE and MANAGER.EXE, sized 353792 bytes and 348672 bytes. Both of them copy themselves to the Windows directory as a file called NOTE.EXE file name and register themselves to be executed every time Windows boots up.
After this, the trojan gathers information from the machine, including username and password, copies them to an encrypted DAT file and tries to email that file to addresses email@example.com and firstname.lastname@example.org.
This trojan does not spread by itself. It can be removed simply by deleting the NOTE.EXE file and the original carrier file. It is recommended that you change your password if you believe to be affected by this trojan.
Backnote was widespread between Christmas and New Year 1998.