Took one of those apart last night for the same reason. 40 screws to get the thing disassembled to the point where the main board can come out. The only saving grace is that on this particular model, the fan assembly is taped to the fin blocks so it can be pried out without needing to break the CPU/heatsink thermal bond.

The dv7 is a general population model, but the .biz units are the same these days (or worse, as some do require taking the heat pipes off the CPU to get to the fin blocks.)