What is regkey.dat? Should I remove it?

The regkey.dat file is dangerous to the computer system and your privacy. It belongs to a parasite, whose payload may differ depending on its type. While relatively harmless pests may use regkey.dat to degrade system performance, display commercial advertisements or perform other annoying actions, really dangerous parasites may use regkey.dat to damage your system, infect files, corrupt installed software and violate your privacy. DO NOT open this file!
The regkey.dat file is installed and used by SpyDefender 2010.
Sometimes a presence of regkey.dat does not indicate that your computer is infected. It can be an essential system file or a file installed by harmless legitimate software and therefore may not pose any threat to your privacy and the system. Although such cases are quite rare, you should thoroughly examine regkey.dat before completely deleting or leaving it in the system.