Complex sentence: Vikram started his career in 1990 with "En Kadhal Kanmani" which did not do well.Then went on to do more than a dozen film which did not do well in box office.
Split into simpler sentences: Vikram started his career in 1990 with "En Kadhal Kanmani" which did not do well. Then he went on to do more than a dozen films which did not do well at the box office.