Photoshop Jpeg images being saved as Xnview

[nikonuser]

Hi - After pp an image in CS3 and then saving it as a jpeg it is being saved as an Xnview Jpeg file so when I come to open it again it opens in Xnview rather than Photoshop.
This has only started to happen over the past few months so it must be me who has done something different.
How can I get jpegs saved in Photoshop to open in Photoshop please.
I know about right clicking the file and then Open With but I was after a permanent solution rather than having to do that with every file.
Appreciate any help.
Thanks
Dave

 

[billybob99]

When you right click to "open with" there is a option to always use the selected program

 

[nikonuser]

Thanks Andrew, will check that out........ yes, it has changed them.....Thanks a lot
Cheers
Dave