Late 2.5 Quad Core Processor unit removal issue

I have a late G5 2.5 GHz Quad Core PPC and after following all the service notes for pulling the processor assembly out of the case, it is still stuck. 6 screws removed, 8 captive head screws loosened and it doesn't want to lift up...any ideas out there? Are the connectors hard to disengage? I need to get this apart and put in some new heatsink compound before I can use it anymore. It is a single pump model. Thanks so much for the help! Jim