Can you boot into safe mode? (Turn it on, immediately after the Dell splash screen begin tapping the F8 key until you get a menu with Safe Mode at the top. Select Safe Mode with Networking and press Enter).
If you can boot into safe mode with networking, log into your main account or any administrator account. As soon as you get to the desktop, open your web browser and insure you are connected to the internet by viewing your home page.
Please download Malwarebytes Anti-Malware and save it to your desktop from here.
Double-click on mbam-setup-1.46.exe to install the application. When the installation begins, follow the prompts and do not make any changes to default settings. When the installation has finished, leave both of these checked:
Update Malwarebytes' Anti-Malware
Launch Malwarebytes' Anti-Malware
Click the Finish button.
MBAM will download the most recent updates and should start after a minute or so.
From the scanner tab, select a QUICK SCAN and click the Scan button.
After the scan finishes, click on the Show Results button to see a list of any malware that was found. Make sure that everything is checked, and click Remove Selected. When removal is completed, a log report will open in Notepad. This log is automatically saved and can be viewed by clicking the Logs tab in MBAM. Copy and paste the entire contents of that report in your next post.
MBAM may tell you to reboot your computer to complete the process. If so, then reboot into Normal mode and post the contents of the log afterwards.