usually this happens when the computer shuts down untidely,its checking the hard disk/disks for errors if it doesnt run go to command prompt,ie start -programs-acessories-command prompt,then type chkdsk/f,this should fix,the hardrive,meaning volume c.have you checked the bios[cmos battery.]you can find everything you want to know about settings etc in the mmc section ,loads of stuff there after all xp operating systems are around1.5gb in size,of course you,ll only find mmc section in an operational operating ,it is inwindows xp sp2,etc,well worth a look,just search for it,or look at another computer with mmc section in it,then when yours boots up,you can use your computer,hope this is use full,cheers.
richard
January 2010