If you don't know, the easiest way to tell is watch the monitor when your computer turns on. You'll see one of these on your monitor:
Examples of your computer make would be Dell, Gateway, Compaq, IBM, Acer, etc. The model number is usually displayed on the front cover, such as Inspirion 8100, Pesario 5300, DeskPro EN for example. It is also possible to find information on the model number by locating the serial number label, usually found on the back of your computer (where all the cables are plugged in.)
There are several ways to find the size of the hard drive in your computer. Possibly the easiest and safest way is to the following:
1) Launch Windows Explorer
2) Expand "My Computer" and locate the C: drive.
3) Right Click and select Properties. The size is generally listed as GB or MB. In this example, the C: drive is a 12 GB capacity.
Your computer Random Access Memory (RAM), usually measured in Megabytes, can usually be found by right-clicking on the My Computer icon on your desktop, and selecting Properties. You will find your RAM size just above the "Support Information" button.