I've searched for and found other instances of my problem on here, but the answers given weren't helpful to me, so here goes:
I have an install of Windows XP Pro that failed to boot, with an "Operating System Not Found" error, after a software install. I've slaved the HDD with another running XP to run a virus scan, defrag, and check for errors. Virus scan came back clean (AVG 7.5 Free Edition, fully updated), and the Windows disk check utility didn't report any errors (I don't remember if it automatically reports or not. I miss the old DOS scandisk!). Apparently, the disk check did do something, because it then booted to a screen saying that "<windows root>\system32\hal.dll" was missing or corrupted, and advising me to reload it. I did that by booting into the recovery console with the XP CD. Then got a message that "<windows root>\system32\ntoskrnl.exe" was missing or corrupted, so I reloaded it, too. After that, I got a message that "Windows could not start because of an error in the software. Please report this problem as: Load needed DLLs for kernel." What I need to know is, which DLLs is it referring to, so that I can load them?