This article outlines the four common causes of a computer system slowing down, which are:
Your system may not have enough RAM
Your system has a lot of data clutter
You have too many applications and programs running on your system
Your system may have been infected with malware or a computer virus
Your system does not have enough RAM
RAM, which stands for Random Access Memory, is a form of computer data storage. It can come in two forms - "static RAM (SRAM) and dynamic RAM (DRAM). In static RAM, a bit of data is stored using the state of a flip-flop. This form of RAM is more expensive to produce, but is generally faster and requires less power than DRAM and, in modern computers, is often used as cache memory for the CPU. DRAM stores a bit of data using a transistor and capacitor pair, which together comprise a memory cell. The capacitor holds a high or low charge (1 or 0, respectively), and the transistor acts as a switch that lets the control circuitry on the chip read the capacitor's state of charge or change it. As this form of memory is less expensive to produce than static RAM, it is the predominant form of computer memory used in modern computers.
Both static and dynamic RAM are considered volatile, as their state is lost or reset when power is removed from the system."
When your computer's RAM is insufficient, the speed in which your systems process information and access the hard disk will be diminished as there just isn't enough space, where your system struggles to use the hard disk as an extension, commonly refered to virtual memory.
One workaround would be to increase the RAM of your computer system.
The following articles in the Community Knowledge Base may be of guidance:
A system's performance can be dramatically impacted if there is a lot of data clutter, where fragmentation is one cause. Fragmentation is:
"a phenomenon in which storage space is used inefficiently, reducing capacity and often performance. Fragmentation leads to storage space being "wasted", and the term also refers to the wasted space itself."
Other forms of data clutter include huge data hogs comprising log files, error reports, Windows Update backups, and browser caches.
Users are advised to regularly carry out housekeeping work through defragmentation of the hard drive, or the use of various clean-up utility programs.
You have too many applications or programs running at the same time
Having many programs opened on your computer can cause a significant drain in your computer's performance and slow down overall system speeds.
The moment your processor hits 100%, your computer will lag.
Users are hence advised not to have too many applications and programs running on their systems at any one time.
Your system may be infected with malware
Malware, or malicious software, "is software used or created to disrupt computer operation, gather sensitive information, or gain access to private computer systems. It can appear in the form of code, scripts, active content, and other software. 'Malware' is a general term used to refer to a variety of forms of hostile, intrusive, or annoying software."
Users are advised to keep their anti-virus software updated.