Your computer is almost new, it is a pretty decent system and now it has suddenly slowed to grinding halt.
The main reason why many people suddenly find themselves in front of a slow computer is often very simple: malware. The slow computer has been overrun by spyware, adware and other computer viruses. It happens to anyone with a connection to the internet and without any kind of security software installed. It is not a matter of "if", but "when".
Malicious programs require ressources from the CPU and RAM as well as any other program. The longer you stay connected to the internet without any security software installed, the more malware you will accumulate resulting in a slow computer. The programs run in the background, so you most likely wont even notice them. A slow computer in this case will be slow at any task. Booting up, opening documents, viewing emails and surfing the web becomes almost impossible as time goes by.
You may find that it has not been that long since your slow computer was running smoothly and you are puzzled as to how things could get so bad in a fairly short period of time. A possible explantion for this is that many computer viruses create what is known as "backdoors". These programs are designed invite other malicious programs to join the party on your now already slow computer. So as your computer attrackts more viruses it becomes slower at what appears as an exponential rate.
Finally your slow computer becomes almost impossible to use and there are only two ways rectify the situation. The easiest way is to try and download and install a security program and have it clean up your slow computer. If this fails you will have to completely reinstall your system and of cause make sure to install a security program afterwards.
The problem with a slow computer in this situation is that the computer has often become so slow that it is impossible to perform even the most simple of tasks. Furthermore, with so much malware infecting your system there is a good chance that you have attracted a few that actually targets and disables security software or blocks access to security websites.
A suddenly slow computer is very often a cleat symptom of several malware infections. It is therefor extremely important to act immediately, when you experience this. Make sure your security program is fully updated and run a complete system scan - even if it takes a long time on a slow computer. If you do not have a security program you should get one is quickly as possible.