how can I clean my computer from incoming threads and error and warning messages

Adware removal/prevention:

http://www.adwaremedic.com

Learn how to identify fraudulent "phishing" email:

http://support.apple.com/kb/HT4933?viewlocale=en_US

How to report phishing scams to Apple:

via email to: reportphishing@apple.com

It's best to describe the problem in as much relevant detail as possible, rather than what you think is causing it or how you think it should be solved.

etfaver wrote:

I have a number of threads and error message on my system. How can I delete them and optimize my system?

What are you referring to as "threads," and where are you seeing these error messages? What do the error messages say?

Be aware that your system does not need "optimizing."

etfaver wrote:

My system is slow and I like to know how I can speed it up. I was told that a number of malicious threads and error messages are downloaded every minute, slowing down my system.

These are two very different things. First, who told you this nonsense about "malicious threads" and error messages being "downloaded"? None of that makes any sense at all, so whoever the source was should be ignored.

Was this a message in some pop-up in a web browser? Or did you get a pop-up with a phone number and call it, and the person on the other end told you? In either case, that was a scam, using made-up terminology to try to scare you into doing what they wanted. See:

Tech support scam pop-ups

As for your system slowing down, see my Mac Performance Guide for some general help. Whatever you do, do not install any kind of "cleaning" utility, or any other tool that promises to automatically "speed up" or "optimize" your system. Such programs are all junk, and are borderline scams.

(Fair disclosure: I may receive compensation from links to my sites, TheSafeMac.com and AdwareMedic.com.)

I was told

By whom? Did you get a browser popup telling you to call a number for tech support?