If I am reading the specs for this right, you are using the "ATI RADEON 7500 Mobility video chipset". You'll need to make sure you have the latest drivers. If that doesn't include the "Catalyst Control Center" (ATI driver utility) you'll need to use windows to manage the desktop mirror.
- Right click on the desktop and go to properties.
- Click the settings tab.
- You should see two screens.
- Make sure that neither one has “Extend my Windows desktop onto this monitor” checked.
If you only have one screen on the settings tab, and you don't have the ATI driver utility. Either IBM has their own utility to do this, or you'll have to go to ATI (now AMD) and dig through the driver archives until you find a package that has the driver utility. That one should give you the option to clone screens onto the S-video port.
As a final thing, you might be able to access the Utility from the Advanced button on the settings tab. There may be a tab for ATI in there.
Hope that helps