I and my many friends using Internet Security suits. Is this way enough for being secured ( theoreticly of course ) or is the better way using different programs for different functions/problems

Generally an anti virus and maybe an anti malware real time scanner are plenty.

An excellent freeware anti virus called avast is perfect for fighting viruses.

If you want to stop malware, the real time protection with Windows Defender or Spybot 1.5's TeaTimer will be great protection.

Should you desire a firewall, Comodo Firewall Pro is the best freeware firewall (better than payware too) you can get.

I and my many friends using Internet Security suits. Is this way enough for being secured ( theoreticly of course ) or is the better way using different programs for different functions/problems

You're well on your way. As suggested above, install Microsoft Windows Defender and Spybot - Search & Destroy, which are both freeware and which will help you protect yourself against spyware. Keep in mind that security is more than just having the right software installed. Configure your system properly. Do not use an account with administrator user rights for your every day work; only use an administrator account when you really need to have administrator user rights. Disable unused services and uninstall unused software. Make sure that your operating system is up-to-date. Proper software is worthless if you do not update it frequently and if you don't configure it properly; have it scan your system on a regular basis for instance. One of the most important things to use is however your own brain; don't simply click on every link, don't simply open every file you receive or download. Handle with care.

Security is not something you buy, it's something you practice. Having software that you use properly is at least as important as how well the software functions. As to practice, a layered defense of firewalls, NAT, antivirus and antispyware, and good security practices (like not running Windows as an administrator, ever) are just as crucial as which software you buy/run.

thank you very much for your dear comments. But Generally I saw that many of you are talking about using different programs for different functions.I have had a bad memory about using different security programs at the same time. One day I installed Kaspersky Internet Security ( KIS ) and I downloaded the Norton Internet Security ( NIS ) trial version. I have restarted my PC than NIS and KIS are tried to scan both of them and my XP felt down. Do you think that can be a coincidence by using multi-security programs?

You should never use more than one antivirus at one time. And on that note, you should never use Norton/Symantec products for anything. They're all bloated resource hogs.

I generally find that suites have one or two excellent parts and the rest is average or crap.

With separate programs, I can get the best of each.