Well Sitro to make a pk3 all u need is Winzip.There are 2 ways the way that doesnt always work n the one that normally works.
the on that doesnt always work is put all the files in a zip file and rename it assetso.pk3
and the other way is To add the files to winzip.then in the add to archive box just retype the assets0.zip to assets0.pk3
Well thats how i think u make a pk3 thats how some guy taught me n it worked.
and Darth Kiran yes if u deleted ur assets u truly would be f***ed.just reinstall the jk2 and ull get it bak