how and where are you saving them ?
if you don't know that than that might be the issue
try going to file / save as
and putting them in a folder that you know where it is so you can retrieve them later
if you dont save them as a project but as a jpg or other type of graphics file than you wont be able to pull them up as a project again
and if you do know that try going to file / open
and browsing to the folder you saved them in and opening them
I can get you my phone number and log in remotely to show you exactly what is going on and how to save them so that you can be sure you can open them again in the future.