Replacing cooling fan in ACER ASPIRE 3620 Notebook

Question

Hey guysI have an Acer notebook Aspire 3620..The colling fan is fried and I need to replace it. The problem is that even after I remove all the visible retaining screws I cant get the cover off in order to access the fan. Is there a trick to it or am I missing some hidden screws.If there is anyone there that can help.....I'll remember you in my will :-)Thanx a bunch