no keyboard working any more on XP SP3

[Xavier]

hello

i am having a KB problem and using actually the MS virtual keyboard.

to help i must mention that no keyboard work at all with my computer since i
have done some "exotic" antivirus analyses (no hardware or configuration, nor
services change by user).

look: every keyboard (ps-2 or USB) work fine in BIOS and are normally
reognized at computer start ;
KB is still not working at all in safe mode ;
same thing when logging in another user account ;
a start with the last good known configuration changes nothing and
there's no restore point available ;
the keyboard drivers seem to be still available (like "kbdclass"
in "C:\WINDOWS\system32\drivers") but i'm not absolutely sure of their
completeness and integrity ;
in MS hardware manager there's a "PIH keyboard" apearing with no
way to update or uninstall, just an error code nr32 and nothing else in the
keyboard menu (only one KB plugged in).

i hope that those complements could help to find an answer for this issue
without being forced to reinstall OS

anyway, many thanks to give help !