No manual needed.
Firstly, try right clicking the file to see if you get any other progs to view your file.
Right Click| Open with...
If you see Paint (Windows prog) try that. Then, File| Save as| .jpeg, for example.
Picture Manager is your default file viewer for .tiff files. You can change this, but need a program to change it to.
May I suggest Irfanview, (Fandabidosi prog, and Free), accept defaults, (unless you are an advanced user, in which case, do what you need to).
After install, reboot.
Go to your image file.
Right click.
Irfanview should now be an option.
Open File.
I don't have my main comp with me, but you should be able to do: File|Save as, or Image| save as... sorry can't help further, as can't quite remember the exact selection.
Save as... jpeg, or bmp or what you want.
Report back!