All applications are opening with notepad!?

So my friend sent me a .lnk file and i recognized the name and i thought i needed to open it with notepad. I forgot to un-check the box for open all files of this type with this program and now all my apps open with notepad! I can get into the system files and run the program through there without using the shortcut but that gets kind of tiresome looking for each file. I have since reset my computer if that helps at all, i want to know if i can reset this? Or at least cancel the open with notepad so i can re-create all my shortcuts!