Don't buy from Dell

I contacted a Dell computer technician and was advised to speed up my computer I needed to purchase additional memory. I purchased two 512 MB memory modules from Dell on 12/23/2008. The product arrived on 12/31/2008. I installed the new memory and my computer repeatedly crashed. Apparently the modules are defective or not compatible with my Dell computer system. I contacted Dell to return the modules for refund on 1/21/2009 and was told by their representative that I had passed their 17 day return window and would not be eligible for a refund. I asked for credit toward a new purchase and was denied. I am now out $181.61 for the purchase. I post this so that you can consider my plight before buying from Dell. Please let us know if you have any similar experience.