I will assume you are using the PS3Eye and not the EyeToy for PS2.
By Old computer, You need to indicate if you have one that has full-speed USB2.0
If it is a Name Brand CPU then indicate what Model. If it is a Clone, or homebuilt, You are on your own to determine if you have USB2.0 or just USB 1.1
(Here is a Clue: If you plug in the camera and a Task Bar Popup suggesting you Plug-In the USB2 device into a USB2 port, then you are running USB1.0 and the EYE will not work.)
If you have USB2.0 and it is full speed, then use the CL Eye test, and select your camera device (It will be PS3Eye) and then use the Adjust Filter Pin…
Set the Size to 320x240@15fps and press Apply and OK.
If you cannot get video, then something is wrong, and it is likely related to the USB drivers and chipset. (Fix that, and it should work.)
The PS3Eye works on Lenovo S10 with a 1.6Ghz Intel Atom.—but I usually use the S10’s built in webcam…
-sean