When many computers have been hacked to turn them into zombies computers, we call such a group a Botnet. Those computers are being used by cyber criminals to send spam emails and/or to attack websites. If your computer is going to get infected by some “bots”, chances are it will become part of a Botnet and your PC will then be another zombie one of that group. Your computer will be controlled at distance by some hackers using a control server and bot-herder command. Those Botnets can hurt networks, websites, personal computers, and more. They are one of the most dangerous problems over the Internet. Problems like viruses, malware, spyware can also be distributed via those Botnets, besides all the spam emails. They can do 2 others things: Dos (Denial of Service) and DDoS (Distributed Denial of Service). Those attacks on system servers happen when those Botnets are trying to overload the servers with many, many requests. Being unable to cope with such requests, the targeted servers will simply freeze and be out of function. Here Remote Computer Repair you can find a great online service ready to repair any problems your PC may have.
The usual way you can get infected by a Botnet is via viruses and trojans carrying such threat. These Trojans and viruses may be delivered to the user in the form of spam emails or they could get downloaded from malicious websites, posing as essential video and audio codecs. Once it has infected your PC, the malicious program will connect itself to its bot-herder server and be ready to do more damage. Like preparing itself to send lots of spam emails, or to start attacking some websites or to spread itself to others PC around the world. Most PC users will not even remark that they have a Botnet unto their computer and thus none of the previous activities will be easily detected. So to detect such a threat is very important. This site Spyware Removal has good infos about spyware removal.
If you do notice your PC is slowing down, this might be a sign it is infected with a botnet. If you do notice that your internet connection is not as fast as before, think that the Botnet is using lots of bandwith to achieve its malicious goals. If your browser has some strange behaviour or if you do notice you are losing disk space without reasons: those are signs you may have a Botnet on your PC. Your PC might be infected by a botnet if you do notice that your browser (Firefox, IE, Chrome, ..) is closing with no apparent reasons or its homepage is a different one or if your desktop has been change a lot.