Hi Chris,
I would recommend you to try the steps mentioned below to troubleshoot the issue:
1. Disconnect any external peripherals like printers, to check if any of the external devices are causing the issue.
2. Also, perform flea power on the laptop. Remove the AC adapter, battery and any external peripherals connected, now hold the power button down for 10 seconds to drain static power. Restart the system and check if issue is resolved.
3. Try to boot to Safe Mode. To boot the computer in Safe Mode, please switch on the computer and start tapping the F8 key which would take you to Advanced Boot Option screen. Using the up and down arrow key, select Safe Mode to boot the computer into Safe Mode.
If the system boots up in Safe Mode, you may perform System Restore to roll back the system to the time when it was working fine. Refer to the link: http://dell.to/1bN4CBi
4. If you are not able to boot the system to Safe Mode, boot to Windows Recovery & try system restore outside windows environment. Refer to the link: http://dell.to/1bN4CBi
5. Also scan the system with the antivirus you are using on the system.
6. .If the issue still persists, run hardware diagnostics. Refer to the link for instructions: http://dell.to/RO1v0p
7. If all tests pass, you may perform Operating System Reinstallation using the Windows CDs. Refer to the link: http://dell.to/182uwwT
Note: All data would be deleted while performing Operating System Reinstallation.
You may also watch an online video on Windows not booting up issue: http://dell.to/17OZeMq
Hope this helps.
Thanks and Regards
Priyanka S