The inspiron 1100 does not come with a touch screen option - Dell's only touchscreen laptops are a couple of Studio laptops (I think 17s?).
The only option that I know of is to replace your screen with a touch screen add-on. I placed a link below to an example (I know nothing about this website, it was just the first one that I found).
Touchscreen Add-ons for Monitors and Notebooks
In my opinion, its not worth the couple hundred bucks that it costs, but it's your computer.