Computer won't boot up after updating to SP2

Ok guys, yesterday i was just doin the good old maintenance on my dad's laptop (spywayre, virus, updates, and cleaning up) so i did scans and cleaned the registry and also was updating to SP2... but when it was finished, i think, the laptop turned off (restarting after the installation) and then when it turned on, it asked for a password, anyways, the password check passes through when i type in nothing in the password box... and then windows starts openin up, and i see the wallpaper then "windows explorer" crashes and the laptop just stops with the only the wallpaper and nothing else on the screen except the mouse... The same thing happens with the safe mode too... and also when i use the "Start with the last known working configurations"... I dunno what to do? can anyone help please?

Also i wanted to just reinstall the windows files without formatting but my dad's laptop's recovery disk only allows a fresh install with formatting... (he has a toshiba m40).. does anyone know how to install a fresh copy without formattin with this recovery disk?

Thanks for the help guys!

 

You need the System Repair option from the Windows installation CD. Are sure you haven't got this option? Otherwise you have no choice but to connect the MS support team, maybe they will be able to help..
Haven't you created any backups before the SP2 update? Maybe using Windows backup option or any third-party software? It could be significantly improve the situation..
Generally speaking, it's recommended to backup data if you don't want to lose it. Even if you use any paid programs like True Image or Ghost for it, anyway you pay lesser then your data costs.