Shari, can you PM me your keywords exactly as you are searching for them so we can check out the result here?
----
There are a few possible off-the-top reasons for this - there's the regular 'Google Dance' that sends sites bouncing around each time Google does an update.
Also, Google queries are sent to one of any 10 Google data centers and all data centers do not produce the same search results.
The other possibility is if a browser has spyware attached to it, that will affect the search results - but doesn't seem likely to be the issue in this case.
Once I have a chance to check out the results for myself I might have a better idea what's going on