There are many PDF viewers on the Internet but if you are looking for a free PDF viewer then you can try with Sumatra PDF. Sumatra PDF is an open source PDF viewer for Windows. I use it on my machine because it has got many good features. One of them is it’s file size. It has got a simple and minimalistic design. Moreover it is portable. So you can actually copy it to your USB drive and use it anywhere.
SumatraPDF works on Windows 2000, XP and Vista.