In Office XP: Tools | Autocorrect and uncheck all features not required
in Office 2007: Click the Office button ( multicolours circle on left top
corner); at the bottom of the next dialog click Word Options (or Excel
Options, etc); open the Proofing dialog and uncheck each item not required.
Note: that in either version, what you set for AutoCorrect in one app (Word,
for example) is also set in all other apps (Excel, PPT)
best wishes