For Office you must install a font before starting an Office application otherwise Office doesn't know about it.
how can i use these fonts with MS Words...? i have already installed some fonts
How did you have install your font ?
If the font are installed correctly on Windows, you can use it with all softwares, including MS Word.
To know how to install fonts, look at the FAQ : http://www.dafont.com/fr/faq.php#win
For Mac users : http://www.dafont.com/fr/faq.php#mac
Look my message just up of yours.
All times are CET. The time is now 18:55