Unable to Update Virus Database

Version 7 uses the same database as v5.8 and newer. You can keep on using 5.10 for quite a while. Even if the database format would change then history shows that Comodo will keep on providing older databases. At this moment the v4 database is still provided for.

When deleting the bases.$$$ does not help try stopping and starting Comodo Internet Security Helper Services under Services. Services can be found in Control Panel → Administrative Tools.