installing IMovie

Good day everyone,

I rebooted my computer recently because it was lagging too much.

Only problem being I can not re download I movie, the App Store wants to make me pay 15$ for it while I already had it before.

I need this application a lot, and since I only use Mac OSX 10.9, I can't find any IMovie app anywhere...

Thanks for your help, and I hope to get a useful answer!

Gaspard T