Hello Daisy,
Thanks for your reply. As even after performing system restore and changing the BIOS order your computer is booting up very slow and working very slow, so I would suggest you to perform the steps given below:
Method 1: Run Microsoft safety Scan
Here is the link for running a Microsoft safety scan:
http://www.microsoft.com/security/scanner/en-us/default.aspx
Note: Any data files that are infected may only be cleaned by deleting the file entirely, which means there is a potential for data loss.
Method 2: Boot in safe mode and checkTry to boot in safe mode and check do you still have the same issue:
Here is the link for booting in safe mode:
If it works fine in safe mode, perform clean boot.
Here is the link for performing a clean boot:
http://support.microsoft.com/kb/929135
Note: After you have finished troubleshooting, follow these steps from section “How to reset the computer to start as usual after clean boot troubleshooting” to reset the computer to start as usual.
Method 3: Disable security software installed temporarily
Note: Antivirus software can help protect your computer against viruses and other security threats. In most cases, you shouldn't disable your antivirus software. If you have to temporarily disable it to install other software, you should re-enable it as soon as you're done. If you're connected to the Internet or a network while your antivirus software is disabled, your computer is vulnerable to attacks.
Also refer to the link given below:
Note: Any data files that are infected may only be cleaned by deleting the file entirely, which means there is a potential for data loss.
Please provide us the Event Viewer logs. Here is the link for providing Event Viewer logs:
Open Event Viewer
http://windows.microsoft.com/en-US/windows7/Open-Event-Viewer
What information appears in event logs (Event Viewer)?
http://windows.microsoft.com/en-US/windows7/What-information-appears-in-event-logs-Event-Viewer
Try to follow the steps given above and let us know the results.
Thank you.