SharePoint - "Check Out" option missing - Asked By Kathy Liddle on 28-Mar-13 01:01 PM

We have a user with issues checking out and editing excel files from our sharepoint site.  He is being prompted "Do you want to open or save Document name from servername".  Once he does he has the option to "Enable Editing" but no option to check out or back in.  This was happening earlier this week and he restarted his browser and it worked.    Any ideas would be greatly appreciated.

He has Windows 7, IE 9, Office 2010 and we are using WSS 3.0
Thank you,