Thanks for posting. Apologies that your system is not performing as expected.
Please post the model number of your computer so that we may give a more informed answer to your questions.
Here is information from the Dell knowledge base you may find helpful:
If you still require assistance and the system is under warranty, you may contact me privately. Be sure to include your personal information (name, address, telephone, email) and your computer's service tag number in your message. Thanks.
If there is no warranty, then you could contact our Out of Warranty team to get a quote for a paid service request.