Title sums it up, but in more detail:
On one computer (regardless of account used) when attempting to click any of the "checkout" buttons on Overstock.com it simply reloads the page to Overstock.com.
I have used the account on another computer successfully. I have used a different account on that computer with the same issue.
I have attempted this in IE and Chrome with no success.
I have cleared cache and cookies on both Chrome and IE with no success.
I have done a system restore to a date prior to the last known successful checkout on Overstock.com with no success.
Based on the fact that I can use the account on a different computer with success and different accounts on the computer without success, I do not believe the issue to be Overstock.com related. However I've hit a brickwall and don't know where to go beyond. My best thought is it's some peculiar issue on the computer directly or there is somehow some issue with the modem/router or CenturyLink itself. In that thought I even put the computer outside the DMZ but to no success. I honestly have no idea where to go with this and Overstock's answer is to simply use another computer.
Barring a better thought, I will be attempting to connect the computer to a wifi hotspot later this afternoon in an attempt to rule out the modem/router or CenturyLink. If the issue persists after being on the hotspot then I'll know for sure it's the PC, and if not then I've at least narrowed it now.