Hello Misaal,
You said that your computer is working fine in safe mode but it gives you these problems in normal mode.You hae already checked up the device manager and all seems fine.I think that there is some startup progrm that is causing problems.I would like you to perform these steps and let me know if it worked for you.The steps are as follows :
(1.)Click on START and then click on RUN.
(2.)Type MSCONFIG and hit OK
(3.)Go to STARTUP tab and click on DISABLE ALL.(We can enable your Antivirus and DSL programs later)
(4.)Click on APPLY and then click on CLOSE.Click on RESTART and let it restart normally.
(5.)If it boots back normally, 'Check' the message "Do not show this message on startup......"on System Configuration Utility window.
Now try and use your computer in the normal mode and tell me if its working fine.
Also tell me the name of your Antivirus software and your internet connection type.
Thanks,
Kzhitij