Is There A Very Small, Fully Functional Pc That It Smaller And Similar To Theones Nurses Use At Hospitals?

I work full time in a factory but keep books for my brother’s restaurant/bar. I have a terrible time with my desktop computer and need just a small, basic computer that is Windows XP compatible without all the bells and whistles. All I really need is the operating system, Microsoft Office Professional, and Quickbooks Professional. I can use the internet and update their website from my desktop or my oldest son’s desktop, but I need a computer that I can carry with me when my brother needs immediate information.