Removing Dell Latitude D610 Fan

I want to remove the fan just so I can clean it and also to see if there's any dust in the heatsink. But the cover of the Laptop doesn't wanna open wide enough for me to remove the screw that is right under the cover, which is this one: https://d3nevzfk7ii3be.cloudfront.net/igi/C1vWYtZl3TUAAeeu.huge I have been following these steps and that's the one I'm stuck on: https://www.ifixit.com/Guide/Dell Latitude D610 Fan Replacement/22663 I don't wanna damage anything by using a lot of force to open it but the cover seems too strict. Is there another way to open the Laptop?

 

Here you go:
ftp://ftp.dell.com/Manuals/all-products/esuprt_laptop/esuprt_latitude_laptop/latitude-d610_service%20manual_en-us.pdf