MASS EFFECT 3 lost

Hi

Last Sept 2012 I both a ME3 PC games and install it ot my laptop (i even both all the DLC via Origin) thing rynning smoothly not untl this Sat May 04 2013 when I install an Anti virus on my laptop AVG and Avira to be exact.

My anti virus remove Origin Exe and ME3 exe saying its somehow virus infected.

I've checkthe Origin folder and ME3 folders, they are still there (including DLC files) but the exe are missing.

I've got no problem re installing Origin my problem is my ME3 I still have the Original Disc in me but I lost my product key .

My question is what do i need to do to make my ME3 run again

ps ( out of desperation i remove my anti v-virus)