Dell Laptop slows down on its own

I have recently purchased a dell ispiron 3552 from game stores in Gateway, I use it purely for work and it worked perfectly for the first 3 months, I have updated and scanned my pc on the regular, but since this morning my PC has been very slow and I was unable to even open my documents let alone use the internet. This is my second Dell laptop as the older one did not give me reason to complain. I am very disappointed with this laptop as its brand new and I did not expect it to give me so much of issues at such a short usage, I had to spend money using computer cafes to complete my work as it has been very difficult to complete my daily tasks as I have spent a lot of money on this purchase thinking It would deem beneficial to me. I am not disputing a return or criticizing your company I just want what I paid for. Whats the use buying a laptop if you cannot use it? I have been to the store and I have seen many customers complaining about the same issue, Is there a batch defect with these Laptops, I would like you to give me confidence to continuing buying Dell products and please sort out my laptop to my satisfaction I have 2 year warranty with Dell and 1 year with Game, I would also like to see a actual report of the issues of this PC.

I would like to hear from you soon, as this is an inconvenience to me and my work.