Replacing the ROM chip on a hard drive PCB

[amyk]

Damage doesn't have to be visible to the naked eye for the drive to be inoperable. If you can actually see bent parts, scratches on platters, etc. it's going to be far beyond recovery...

As for opening the drive, don't do that if you don't have a clean environment or aren't prepared to realign the heads - was it a WD? Those have the top screw for the head arm control the alignment: