what's different between this machine and all the others? Maybe the MBR is bad (do a fixmbr).
Only difference I know between functional and non functional is this is HP hardware and our standard platform is usual Dell. The machine did function prior to being rebuilt, and is the same OS and Service Pack and same version of EEPC, I think it was initially 5.1.9 and it upgraded to 5.2.5 and this time it was a clean 5.2.5 install, but that same clean install works fine on other machines. Hardware BIOS settings haven't changed either since it was in a functional state and now. Possibily there is a replacement hard drive but still IDE which is what it was prior.