Recently synced bitcoinqt fully over around 36 hours or so without problem. I'm now trying to tentatively test it out as a newcomer and when I run it, it says "out of sync" No block source available 37 hours behind and 0 active connections to Bitcoin network. Should it automatically update each time it is run? Should it automatically connect to the network? Can I use only when fully synced? Apologies for the naivety of the questions but would appreciate someone's time with help?
Although it seems to have resolved itself, there can be other causes of this. Windows firewall will sometimes block my wallets from syncing. (I don't think this is causing your problem, but it may help someone coming to this question via search with the same problem.)
To diagnose this problem, type "firewall" into the start menu and click "Windows firewall with advanced security". You can then click "Monitoring", then "Firewall" on the menu to the left. Sort this list by "Action" and see if your wallet program is being blocked.
If it is, click "Inbound rules" and sort by name, look for your wallet program. If it's being blocked, right click and disable the rule.
Likewise, you should check "Outbound rules" in the same way.