Everything opens in notepad? WHAT?!

[Retribution]

Hello techies, I am not very well versed in computers and at one point, I decided to open a TXT file with notepad and now everything is opening in notepad, including games, internet (on different computer), as well as Word and skype. I've googled the issue and a few have found solutions, however, I have no idea what on earth they said, let alone how to replicate it onto my computer.
Thanks in advance.

Edit: forgot to say I have Windows 7

 

[lt.thomas]

lol i had a simlar problem with my fathers computer about 2 years ago, try
checking your C:\ and or D :\, as the computer may have moved ALL your files over to which ever drive is backup, leaving nothing but shortcuts, if thats what happened the solution is simple: move all files back... if however the files are still in their right place or have been deleted, you might concider try set your computer back a few days back with the recovery tool,
another possible theory is that your harddrive is getting full and gets "confused" (couldn't find a better word for it ) about how to start each program, in which case you just delete some stuff to make more room....

if none if these sulotions work you have to run the backup to completely reset your computer


-Lt.thomas