Today I recieved email from comodogroup about testmypcsecurity.com where one could test the security of the PC. but when I downloaded the files, many of the files were detected as virus or malware by the comodo antivirus. now this testmypcsecurity.com is a joke or is comodo really serious about offering such a service

i am totally confused.. Comodo please clarify.
Comodo Internet security v3.8
win xp sp2
Welcome.

TestmyPCsecurity.com is legit. The AV detects those files becuase they are very similar to malware (basically they are kind of like malware), but they are harmless.
"Leak tests are small, non-destructive, programs designed by security experts that deliberately attempt to bypass a firewall's outgoing security measures. The rationale behind them is painfully simple: 'If this test can get past your computer's security defenses, then so can a hacker.' Explicitly designed to help identify a firewall's security flaws, leak tests provide the invaluable function of informing the user whether or not their security software is providing adequate protection.
The tests pose no real threat to the security of a computer as they are harmless simulations of the attack techniques typically used by Spyware and Trojan horse programs. There are many firewall leak-testing programs available – each one designed to exploit a particular flaw and each using a particular attack technique to break a firewall's standard protection mechanisms."
Running these tests will do no harm to your PC. They will just test your PC's security.
Just disable your AV when running them.