set default programI often get calls from people saying that they are trying to open a file and the wrong program is opening it.  This is easily sorted by doing the following steps (I will use a PDF file in this example);

1. Close all running programs (email, internet etc.)
2. Click start and where it says search type in Default or in Windows 8 just type in Default
3. Click on Default Programs in the list
4. Within Default Programs click the link Associate a file type or protocol with a program
5. Wait for the list to be built
6. When done scroll all the way down to .pdf and double click it
7. In the next window make sure Acrobat Reader is selected and press ok

For all other file types you just need to find the extension in the list and choose which program you want to use with it.