After a virus or some type of malware is removed from your system, the computer will not boot. You never see any start-up screens. You see nothing but a black or blue screen, possibly with an error code or message.
First, verify that the atapi.sys file is no longer in the “C:\Windows\System32\drivers” folder. (If you find atapi.sys in this folder, there may be another problem and this solution may not work.)
Locate a clean copy of atapi.sys from another location on this computer. A simple file search should locate several copies. Use the newest copy listed. Probably from
Copy the alternate atapi.sys file.
Paste the clean copy into the appropriate folder.
Reboot the computer.
This completes this repair.
Note: Performing this repair may require removing the hard disk from the affected computer, and connecting it as a secondary or external drive on an unaffected machine.
Access may also be gained by booting the affected system from a cd/dvd boot disk.
The removed virus or malware had attached itself to, or infected, the hard disk’s mini-port driver file. Your antivirus software found and quarantined/deleted the infected file. This file is necessary to boot the computer.
The atapi.sys file is usually the affected driver file in this situation.