How to change file type associated program

Hey!
I have a problem with my computer. Well there are some programs that i use very less often but still i don't want to uninstall them as they might be needed some times. I want to change the default associated program for a file which is changed by to some program that is used by me very less. Example : I use firefox as my default browser but sometimes i need opera too so i installed opera and now that has become my default html browser. Everytime i click a link it opens in opera, where as i want to use firefox. Another Example : I use windows picture and fax viewer as my default image viewing software but after i installed office images open in microsoft office picture manager. How do i change these file association? can anyone help me..!? Thanks in advance.

Hey!
That is quite easy. If you want to change the default program for images right click on any image, click on open with option then select the programs you want to se as default. Check the below box which says Always use the selected program to open this kind of file. Click OK. done next time images will be opened in the default program that you choose. All the best!

Hey!
You can also do it this way :

• Right click on a file
• Click Properties
• Click on "Change" button near "opens with" progarm written there
• Select your default programs and check the below box which says Always use the selected program to open this kind of file
• Click OK

Done! All the best...

Hey!
Both the above ways are for doing the same thing. But that may prove a bit hectic. As there are a lot of images and if you do this with gif image, you will also have to do this for jpeg, png files seperately. The best solution is to be cautious while installing a software. Uncheck the option "Use this as default software" whenever available. All the best!