|The date/time set on the computer, but I don't think that is the cause.|
The root certificates issue was a symptom, not the cause. I thought windows may have been waiting on that service to complete before allowing communication.
Do not do anything to the root certificates.
With this information, I think this is most likely an issue with the connection or router.
You mentioned earlier on that everything is left on all the time because it gets cold in the shop.
There are multiple things that can be the cause:
* The equipment gets too cold overnight. This is a guess since I don't know how cold it gets. When you start the web browser / email client, is the shop warmed up?
* The equipment needs to be rebooted. This is less likely to be the cause, since the problem disappears after 2 hours.
* If you connect via wireless, there may be a temporary source of interference. Check the local surroundings and see if there is anything running during the time of the interference.