customer service research Inc. sent a letter and a check for that amount of $1,600, says to cash the check western union out $950.00 and a $100 service charge, and go buy things at best buy, K-mart or Walmart for the sum of $250 an Internet

Why would a company that does not know you send a valid check for $1400?   If such checks were real the company would be getting ripped off left and right by people who pretend to be someone else on the Internet.   Real businesses do not work that way.  This is not a real company.  It's just a group of scammers that hope you send them untraceable cash transfers in exchange for a phony check.

Here's the scam :   They send you a bogus check and tell you to deposit it.   You are then instructed to spend a little of it locally, but the bulk of the money is to be sent via Western Union (which is like handing cash to a stranger).    In a few weeks, the check makes its way back to the supposed bank of origin and is identified as a fake.    Your bank then demands that you pay back the money you withdrew.  In the meantime, the scammers have disappeared with your untraceable cash.   

Does that sound like something you want to get involved in?     This scam is possible because banking regulations require banks to make funds available on deposited checks before the checks can actually clear at the bank of origin.   The scammers know this.   The victims don't (until they're on the hook for a lot of money). 

And a very common, well known one at that. The check will cash, but then turn out to be fake, and you will be liable for the amount, plus you may even be criminally charged. End of story. 

that anyone still has to question whether crap like this is legitimate. What the hell is wrong with the empty space between your ears to think some random company is going to send you a check for NOTHING and trust you to send the money back etc.. Seriously?

I got the same letter today for 1400.00 with the same instructions. How do I find out if it is a scam or not?

This is a scam. The check will bounce and you will have to reimburse your bank. This fraud usually works like this: you sell an item on Craigslist/eBay. The purchaser sends you the amount for the item along with a very large additional amount for shipping. You are then requested to send any money left over along with the item. The check, after intially clearing your bank, bounces and you have lost the item and the money you have sent. What happened to you is just a variation of this popular scam. Contact the consumer fraud division in your state. I'm sure they will love to have all the info you have.