Why laptop/notebook or pc runs slow?

You find your laptop speed so damn slow or maybe it is freezing (stuck), rebooting without reason or perhaps you are getting the deadly blue screen.

Here are some possible reasons
* Windows Registry Problems
* Not enough memory for all the applications you want to run.(RAM)
* Experiencing hard drive problems
* Poor internet connection speed
* Virus, adware, spyware
* Processor speed
* Speed of graphics card