My computer keeps asking me what i would like to open files with (exe. files)?

I have windows 7 on my computer and recently, for about 3 or 4 days, my computer wouldn't let me access files, the only thing its letting me access is my internet browser. I can't get into MSN, Ares, I can't even get into my system restore to restore my computer and I don't know what to do the only thing i found that would help its rebooting my computer and it said i needed my windows 7 disk, which i don't have and i don't want to reboot my computer because i don't want to loose all my files. What do I do?