ispočetka

1. from the beginning; all over again
   Moraću sve da pišem ispočetka. — I'll have to write it all over again.
   Hajde da počnemo ispočetka. — Let's start over.
2. at first; initially
   Ispočetka mi je bilo teško u Beogradu. — At first it was hard for me in Belgrade.
   Ispočetka ga nisam razumela. — At first I didn't understand him.

The Pravopis recommends the separate spelling iz početka in the sense 'all over again' (početi iz početka) and ispočetka for 'at first'; in practice ispočetka is often written in both senses.