I did something very similar at OfficeMax a while back. I took everything back (less the UPC and rebate receipt) and explained the situation to them. The manager took another package of RAM, opened it up, gave me the stick out of it, and put the defective stick back in the box from the new one. They were happy and I was happy; the new one worked (and is still working) perfectly.
Staples took back a hard drive of mine almost a year later when the head crashed. Gave me a 3 gig higher drive because they didn't carry the other one anymore. She didn't refund the $60 difference in price, but I didn't expect nor necessarily want her to- I was ecstatic the way it was to swap it out for a new one locally!
Shahani, that laser printer wouldn't happen to have been a Brother HL-1440, was it?