Emails being deleted from Inbox

Sounds like you have AutoArchive  enabled for "every 7 days"

1. To globally configure Outlook's AutoArchive feature, select Tools, choose Options, click the Other tab, click the AutoArchive button, and implement the settings you prefer. I like the cleanup to occur weekly, and to be told it's about to run before it does. I also like to collect archival data into one archive (Archive.pst), then as the quarters roll by I manually move data from Archive.pst into quarter-specific archives. I recommend these global settings:

    * ON: AutoArchive every 7 days
    * ON: Prompt before AutoArchive
    * OFF: Delete expired items when AutoArchiving (e-mail folders only)
    * Default archive file -- Archive.pst (path will vary)

2. To set an individual folder's AutoArchive properties, right- click on the folder, choose Properties, click the AutoArchive tab, and implement the settings you prefer. Remember that you'll have to repeat this process for each individual folder you want to archive. I recommend:

    * ON: Clean out items older than 1 Month
    * ON: Move old items to -- Archive.pst (same file as above)

Take a look here for more info:
http://www.thenakedpc.com/articles/v03/04/0304-03.html

The view may be it....also check for a filter. View > Arrange By > Custom to see if the filter is on or off.
If it is on click on the filter button and there is a clear all button.
JW

It was the view setting - thanks Augwest.

Thanks to everyone for their contributions too!