Dell support is available via http://www.dell.com/support/. To properly navigate Dell’s website you will need your service tag. This website can help you identify your service tag http://www.dell.com/support/contents/ca/en/cadhs1/category/product-support/self-support-knowledgebase/locate-service-tag.
Contacting Dell Support through the website varies depending on your warranty status. You can call Dell support 24/7 via 1-800-906-3355, but you will likely need to pay a fee if your warranty has expired.