XP failing to boot on Acer 4220
I have an Acer travelmate 4220 laptop which won't make it all the way through booting up. The windows screen comes up then it checks the hd for problems then it loads as far as the desktop background but no icons appear and it will not respond to any keyboard commands. I've tried 'last known good config', alt +F10 etc and it won't even boot in safe mode. I'm hoping there is a command I can press on startup to restore factory settings from the secret partition to save me having to track down an xp cd to reformat? Any advice and ideas would be much appreciated.