hi jenny
this is one of the most common issues with windows xp,it happens to desktop pc,s aswell as notebooks and is caused by a corrupted boot loader come boot.ini file
a system restore done via a safe mode start-up is one solution however this is depending if the problem is only confined to the current windows xp settings,if the whole boot process is corrupted then this will not work
another reason for crashes is overheating and this is more relevant to notebooks rather than desktops mainly due to the limited cooling found in notebooks
try cleaning the vent(s) in your laptop,these are normally located either at the side or on the back of the notebook and can easily become blocked with dust after a while,and this will significantly affect the performance and temperture of both your notebooks cpu and other hardware
use some air duster(http://www.maplin.co.uk/Module.aspx?ModuleNo=25351&DOY=14m10),and some short blasts of air into the vents will clear out any dust/muck thats acumilated in there over time
after this leave the laptop for a few minutes and then boot up again to see if theres any difference
there is another way,however it depends on the way your notebook is designed,some laptops come with recovery disks,these will return your laptop to its factory settings and will basically return the p.c state to the way it was when you first took it out of the box
however some come with a recovery partition which is a hidden partition on your hard drive(around 8gb) and is initialized by pressing a fkey during post(power on self test),normally f11 or f12
then windows will basically re-install using the files located on that partition,however unlike recovery disks(were you lose all your data) the recovery partition allows you to recover your p.c with or without loss of data
this is a option however remember to back up any data or files that are important before starting the recovery
theres also the windows xp "recovery console" which is used to repair damaged windows xp installations,and is specificly designed for repairing boot problems,however the recovery console is quite difficult to use and requires advanced knowledge
so in reflection theres a few solutions to be getting on with,so try them in this order :
1)boot up and press f8 to begin safe mode,then when prompted choose "system restore",then choose a restore point as far back as needed but not too far
2)if you can manage to use it,try the recovery console,you can find some useful information and assistance at http://www.maplin.co.uk/Module.aspx?ModuleNo=25351&DOY=14m10
3)run the recovery disk/partition however remember to back up any important files/data to a external storage device or removable media
all these methods are tried and tested and all will work,however any problems let me know
good luck jenny !