Microsoft Files Extensions - What are microsoft files and how do I open a microsoft file?

What are microsoft files and how do I open a microsoft file?

File Type Category File Format
.avhd Microsoft Files Hyper-V SnapShot File
.bdp Microsoft Files Exchange Diagnostic Message
.bdr Microsoft Files Exchange Non-Delivery Report Body File
.chm Microsoft Files Compiled HTML Help File
.contact Microsoft Files Windows Contact File
.ctx Microsoft Files Valve ICE Encoded Script
.dap Microsoft Files Access Data Access Page
.do Microsoft Files Java Servlet
.dsn Microsoft Files Database Source Name File
.dsv Microsoft Files DeSmuME Save File
.fdm Microsoft Files Exchange Forms Designer Form Message
.jnt Microsoft Files Windows Journal File
.key Microsoft Files Keynote Presentation
.ks Microsoft Files Kickstart File
.laccdb Microsoft Files Microsoft Access Lock File
.lib Microsoft Files Generic Data Library
.oab Microsoft Files Offline Address Book
.pac Microsoft Files Proxy Auto-Config File
.pack Microsoft Files Pack200 Packed Jar File
.pdo Microsoft Files Pepakura Designer File
.sch Microsoft Files EAGLE Schematics File
.sdb Microsoft Files Custom Application Compatibility Database
.sqm Microsoft Files Service Quality Monitoring File
.uccapilog Microsoft Files Microsoft UCC API Log File
.vdw Microsoft Files Visio Web Drawing
.wer Microsoft Files Windows Error Report
.wsdl Microsoft Files Web Services Description Language File