You got a new system, and been working for a while with it, but you are noticing that your system is not as fast as it was at the time of purchase, no matter what you do your system is not improving its performance. The following might be the reasons for such poor performance of your system.

1) Malware

2) Virus or trojans

3) High Disk defragmentation

4) Lot of registry errors

5) Huge amount of temporary files, cookies and cache.

While the last 2 errors can be solved easily, by defragmentation and disk cleanup (start –> programs–> Accessories –> System Tools –> Disk cleanup and defragmentation). The other three problems require good software, though your system mostly will have a norton or mcafee trail versions installed (all they have is just brand name) they are not really good enough. Also never go for a plagiarized or cracked antivirus, as those can be malware themselves, instead go for the following free antivirus, which are much better than the paid versions of other software.