Identifying

Are Track Changes Being Tracked ?

There is no obvious way to tell if changes are being tracked.
2010 and 2007 - this is indicated on the status bar
2003 - TRK indication on the status bar.
When the Track changes feature is enabled "TRK" will appear on the status bar in the bottom left corner of the screen.
You can double click this as a quick way to toggle track changes on and off
Press the Next button on the Reviewing toolbar - if it says document doesn't contain any

You could also use the Documents > Document Inspector to check.

Does the document contain any Tracked Changes ?

Track changes can be hidden from view

To make sure it doesn't, select Accept All Changes in Doument"

Just because they are not displayed, doesn't mean that there aren't any
The only way to remove tracked changes is to accept or reject them
(View > Markup) toggles display of changes

2010 and 2007 - Review tab > Tracking - menu Original show markup (use the "Show Markup Menu")
2003 - Reviewing toolbar
If you are using ballons then:
Original Showing Markup - displays balloons for insertions
Find Showing Markup - displays balloons for deletions

<< link to remove all tracked changes page >>