Question : No hard drive is recognized

I have this laptop (Dell Latitude D610 Service Tag GGY1Y81) that does not recognize any hard drives.  I have tried about 3 different ones besides the original and also have set the bios back to default without any luck.  In bios it also claims that there is no hard drive present.  The hard drive seems to plug in good because when I push it in I can feel it slide into the connector like it is supposed to.   Am I assuming correctly that something has gone wrong with the motherboard and therefore it needs replacing?

Answer : No hard drive is recognized

As long as you're connecting the data connector and the power connector (may be on one connection bar) securely and turning on the laptop AFTER you plug in the device, the BIOS should recognize the drive if it's good.

Assuming you're using known good drives to test and you're not trying to plug them in while the power is on, I'd say something is wrong with the connector or the motherboard.