Hello and welcome to the forum.
First of all, I'm not familar with "win player" unless you are perhaps talking about Windows Media Player.
Second.... be very careful of opening email attachments that don't have the proper file extensions. Make sure that they are coming from a trusted source, you are expecting them and they are formatted properly.
Having said that, you need to determine what program you have installed that is capable of opening "word documents" (..doc or .docx).
Assuming that you have Microsoft "Word" installed, you will need to set that as you default program.
Right click the Start Button and click Control Panel from the context menu.
Top right corner :"View by:" use the drop down arrow to change to "Small Icons" and then select "Default Programs"
Click the top link that says "Set your default programs"
Select your program from the left column list of "Programs"
Then click "Set this program as default" link near the bottom and click "OK".