How to increase PC Virtual Memory?

When you get an error stating "Your PC's virtual memory is too low", here's what you can do:

(Windows XP)
Click Start button.
Select My Computer. Right click and choose Properties.
Go to Advanced tab. Under Performance section, click Settings button.
Under Advanced > Virtual Memory, click Change button.
If the default selection is System Managed Size, choose Custom Size.
Input your desired Initial and Maximum Size and click Set button. Click OK.

You will be required to restart your computer for the settings to take effect.