(Posting by request from a comment because I don't want the commenting system to kill the formatting.) I'll show you a few examples of the usages of the two words to clarify the difference. 생각하다 (to think) - 어떻게 생각하세요? What do you think? - 저는 ...라고 생각해요. I think that .... - 뭐라고 생각하고 있어요? What are you think about? - 이것 무슨 뜻이라고 생각해요? What do you think this means? 기억하다 (to remember) - 아직 기억하세요? Do you still remember? - 그 분의 성함을 기억 안 나요. I don't remember his name. - 그 친구의 전화번호를 아직 기억해요? Do you still remember that friend's phone number? - 아까 부탁한 것 기억해요? Do you remember what I asked you to do earlier?

생각하다 is to think(想). 기억하다 is to remember(記得).