hi merricat,
If you quarantined the file, it should still be in the virus chest (Maintenance/Virus Chest tab). Select the file and right-click it and select "Scan". Depending on the scan results, you can either restore the file if clean, or delete it if you think it safe to do so. Leaving it where it is will do no harm to your system, even if left there for months.
A file is safe to delete only if it is not a needed windows system file, needed program file for an application or other critical file needed for proper computer operation.