Why do I have to install more memory on my computer?
If your computer has UNDER 500mb of memory, and even if your softwares is 100% clean, it may still run slow and you may not be happy. If you have 500mb of memory, computer will run fast, as long as you don't have too much windows open. For example, two internet explorer window opened with one playing streaming video, and two microsoft word window opened. If your computer have 1gb (1000mb) of memory, you don't have to worry as long as you are not doing the following:editing photos, editing videos, or playing 3d gaming.
Here is a video on how to install memory.