Posting this around, problem with my own older PC, (the shuttle), has loads of stuff on it I want back, so need to get it working again, read below:
Windows looks like it is booting nomally, gets to where user should be prompted to login (standalone workgroup machine), yet the login prompt is not presented, instead, just a blank blue background, mouse and keyboard are responsive (mouse moves, keyboard allows capslock toggle).
CTRL-ALT-DEL does not bring up the task manager.
Same behaviour is evident is safe mode.
Have attempted using last known good configuration, VGA mode, all safe modes including safe mode with cmd prompt - (didn't even get a cmd prompt!), shortcut keys to try to get a run dialog and an XP repair install to no avail.
Any suggestions appreciated, have spent a fair while on this now according to the chart below: