I am troubleshooting issues on a Compaq Presario 2100 series/90us. The notebook pc was brought to me after others unsuccessfully attempted repair. I've spent an obscene amount of time learning and unlearning with some progress,however,the hd is repeatedly,"none" in bios,moreso,not recognized, by Win os,boot,install, etc.HP recommended restore disks,which I tried... I've explored Win opts,Linux,Seagate,Virtual,PXE,image creation,suggested medias,blahblahblah.Lights up as it should,but no luck otherwise.I'm feeling a bit more challenged than I am comfortable with. Any advice would be appreciated.