Welcome to the Community,
Though its a new system i suggest you to run the Dell 32 bit hardware diagnostics.This will confirm if the slow boot is due to any hardware issue.
To start the diagnostics,tap F12 on start up (at Dell logo).When the Boot menu appears, highlight the Boot to Utility Partition option, or the Diagnostics option and then press <Enter> to start the 32-bit Dell Diagnostics.
Press the <Tab> key to highlight Test System Press <Enter> to continue to 32-bit Diagnostics.
Let me know how the test goes and post back any error code/message.
I would have already contacted Support in case you need to exchange the computer. At least get your case on the books today before the 21st day by calling Support. Posting on this user to user forum doesn't count as contacting support.
I tried accordingly and the diagnostic shows no hardware problem. After that it worked normally as I shutdown and after 2 minutes turn it on again. But today the problem is happening again. I tried 'safe boot' option but no result. . . .
Can anybody help me out from this problem !!
Since the Hardware diagnostics passed without any error the problem could be software related. Have you added or installed any new software to your system after receiving the system ?
You can try restoring your system back to the factory settings and see if that helps.if you have saved any important files on the system make sure you back it up before you perform PC restore to set the system back to factory settings.
For help to perform PC Restore use the link below:
Let me know if this helps.