Sorry I never posted what the problem was - after many tries to check out I discovered that for some reason the check out cart did not like it when certain things were together.  In my case it was a monitor. So I saved all the items to the save cart area - checked out with the monitor alone in the cart with no problem. Then I added the other items in the cart and checked out with another order and it worked. I do not know what the issue is with the check out system but this workaround did the trick for me and I hope it works for others
I have been trying to place an order all day - when I get to the choose a payment method (no matter which I choose) it takes me to a 404 error page.  I have cleared cache, cookies, etc. to no avail.  I have also tried another browser with no luck.    Any ideas?
Anyone else having trouble checking out?