Can any technically minded people help me with my computer please?

[wildwoman]

Somehow I have set my computer so that if I try to download pdf files they open in notebook and are complete gobildigook. Does anyone know how I can fix it? Please

I do't know why but I have been trying again. It seems I have adobe reader in my list of files but it is empty. I can't download it as it already exsists but when I try to open pdf files in something other than notepad it doesn't give it as an option. aaaarrrgggggghhhhhhhhhhhhhhh!

I've only bloody done it!!!!!! I am so excited!!!!!!!!!!!!!!!!!!!!!!!!!!