This is a remarkable virus, from a technical point of view, as it is the first multipartite virus. Thanksgiving is able to operate both as a boot sector virus and also as a file virus.
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 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.
As a boot sector virus it is able to infect the partition table on hard disks, storing the original sector on track 0, head 0, sector 4. When infecting diskettes, it will format an extra track, where it stores the original boot sector, as well as the rest of the virus code. When the virus is executed, it will load itself into memory and monitor the execution of programs.
When a non-infected COM file is executed, it will be infected. The virus adds 1253 bytes to all programs it infects.