Hey man, I figured you could use a bit of English to help you out, in case you're unable to comprehend what these fine people suggested. So, "que" and "cual" are two different words, and when to use them certainly does depend on the context. What they both say is true, however, they're both from different Spanish speaking worlds. So, here's a quick tid bit that I'll offer you. "Qué" (with the accent when used in a question) usually means "what". However, it can also mean, "than". Examples: "¿Qué te gustaría hacer?" means, "What would you like to do?" But, if you're trying to say "what" in Spanish, it's imperitive that you write it with the accent mark over the 'e'. If you don't, it means "than" or even "that". "Corro más rápido que tú." means, "I run faster than you." Notice there isn't an accent over the 'e' in "que" that time. "Cuál", however usually means "Which". For example, "¿Cuál es mejor?" means, "Which is better?" Again, notice the accent over the 'a'. I heard it said that it's important to remember; if you're asking a question, put an accent over the strong vowel. If you're responding using the world "which" it's not neessary. "En el caso en cual no sé..." means, "In the case in which I don't know..." I hope this helped out, man!

Depende del contexto. "Qué" se usa para decir cosas como ¿Qué estás haciendo? "Cual" es para preguntar por alguna opción, por ejemplo "¿Cuáles cosas te encuentras haciendo?". Hay una diferencia sutil entre ambas.