There are three best PDF readers for windows.You can download these software free.There are many pdf readers available but here are three best.
(1) Adobe Acrobat reader
Adobe Acrobat is a PDF reader software free available.version in available for windows, Mac OS X, Android, Linux.
(2) Foxit Reader
Foxit Reader is free PDF reader tool.You can easily view, edit, digitally sign print PDF files.Available for windows and Linux.
(3) Nitro PDF Reader
Nitro pdf reader is a commercial software use to create and edit PDF files.Its a free software.
Processor: 1 GHz or faster processor
RAM: 512 MB system memory
Hard Disk Space: 300 MB