|Then maybe you didn't get the connectors on good enough. |
Can you see the POST screens at start up? If not, then boot into the BIOS (setup) screens and disable fast boot and any logos that are enabled.
If the drive doesn't show in the POST screens then something is wrong.
Did I understand you to say the replacement drive is the smae EXACT drive model? Or just hte same type?
If your laptop came with a SATA I type hard drive and you are replacing with a SATA II type drive it may not work. I don't know about laptops but with desktop SATA drives many of the SATA II drives have a jumper on them to throttle the speed to SATA I for backward compatibility.
What exact drive did you purchase?