My IBM laptop (window 2000) was infected by virus, then I made a mistake to delete the lsasser.exe file in the windows, the laptop was just dead, cannot even enter the windows 2000. I am writing my thesis, so a lot of important stuff inside, how can I restore this laptop. And I try to start the laptop with the CD-ROM (windows 2000), it doe not work. How can I do? Give me a hand please!