Notes about the 521 file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries
, unused processes and other unfavourable system settings to identify slowdown issues.
The 521 file type is primarily associated with 'Murray State University Trojan Ring Configuration File'. The Trojan Ring is a ring of students. There are 7,000 PC's, and 13,000 users. All of them connect to the Trojan Ring, and it acts as a firewall, because the common Trojans here look for IPs with vulnerable ports, and the ring bombards it with IPs and vulnerable ports, all of which are static and bgus.