You probably already know how much memory your system has physically installed in it, often times it is import to see how much is actually available for you to use at any time.

Here is one way to check:

1. Open Start > Programs > Accessories > System Tools > System Information.
2. Select the System Summary link at the top of the tree on the left side.
3. Note the value for Total Physical Memory. This is the amount of RAM Windows has recognized as installed in your system.
4. Note the value for Available Physical Memory. This is the amount of unused RAM available to your computer right now.

If the Available Physical Memory value is low when no programs are open (on XP or Vista, anything below 100 MB would be considered low), you might want to look into getting additional memory for your system.