sd card to computer all data gone?? because of termination of process????

I am completely computerly clueless. 

Last night I plugged the SanDisk (E) into the USB port on computer (C)

My goal was to take info. from (E) and burn to a cd (D).  

My understanding is (E) lends (C) the info. until (D) has made nice. 

(E) + (C) + Roxio = blank (D)  

Problems: 

>> started whole process over not a thought that (E) had more to lend (C). 

>> (E)  knocked out off (C) info 2000 went to 0 

>> McAfee did a system update reboot

>> tried fix (E) with a free-to-try program. some pics saved ; music/video who knows

>> I keep thinking somewhere within (C) the info/files are hiding or whatever. 

I hope I am helpable. And (E+C+D) = fixable.

Files not be mine.  

Thanks ahead of time.