If the software was purchased, just use the installation CD to reinstall. Otherwise, it is possible to use recovery partition and CD/DVD recovery available from some manufacturers to have it back (e.g. "Smart Restore" for Packard Bell usually comes with a preinstalled Microsoft Office suite).
Reading files a .DOC file
To view a file in Word format (.DOC file), there is a free tool called Word Viewer.
Use a free alternative
There is a free alternative to Microsoft Office, offering equivalent tools (word processing, presentation, spreadsheet, database), called OpenOffice.org. Here are some of the advantages of this suite: it's completely free, it's simple and effective, similar to that of Microsoft Word, it has support for hyphenation (cutting end of line), an interaction between software suites is made possible and most of all the community is very reactive.
Trial versions (60 day trial) for home, small businesses, schools, corporations and professionals are available by simply giving a hotmail email address, or a Windows Live ID on this link. Remember to uncheck the box offering to receive promotional offers on your e-mail.
Microsoft has opened a new service called OneDrive on which it is possible to use MS Office applications in a web adapted format (limited features compared to the desktop version but suitable for basic use). The use of this service, web applications and online storage space is free for those who have a "Live" account.