Attachment Application association not saving in GW2012

Hi,

The PC:

Windows 7
MS Office 2007
IE 8
GW2012 client.

Issue: File/Application association settings won't hold for attachments in GW.

Description: GIF files were associated with MS Paint to OPEN. They are opening in MS Paint. But now we tried to change it to "Windows Photo Viewer". Yes the box for "always use this program to open...." was checked. GIF files from the PC are now opening with "Windows Photo Viewer" as selected but they still open in "MS Paint" when a GIF attachment is opened from GW.

Tried reinstalling GW client, cleaning registry but that didn't help.

Anyone might have faced this/similar problem?

Any suggestions to fix this would be greatly appreciated.

Regards,
Yaser