Most sites won't load

[#1]

I have a new connection, switched from the last tenants' BT line (which worked fine). Using the newer Sagemcom router. Went live on 29th June, not plugged in until 1st July due to being in hospital.
A few websites (seemingly the main ones, youtube, facebook etc) work brilliantly, faster loading than the BT connection and no dropouts or anything.
The problem is that most websites just won't, full stop. Chrome gives "ERR_CONNECTION_RESET". Worth noting I can still ping these, just not browse them. Possibly a DNS issue? Tried:
-Different PCs
-WiFi as opposed to ethernet
-Restarting router and disconnecting/reconnecting in the control panel
-Using google DNS as opposed to the auto setting
Nothing has had any effect. Additionally, a tracert command to the site shows lots of timeouts in intermediate hops at the ISP end before pinging the final hop.
Is this normal for a new connection? I can't find any note of this happening anywhere?

[#2]

I doubt it's a DNS issue if you've used Googles DNS and you've had the same issue.
Can you try a reset of the router? I've made some remote changes which may help.

[#3]

Hi Splennharvester,
A warm welcome to the forums.
What firewall / AV are you using?  I have recently seen similar issues using Norton AV/firewall, which all went away when I switched off Norton firewall and subsequently uninstalled it and installed something more fit for purpose.  That said the problem returned a few days later ... along with Norton, the replacement product having vanished....

[#4]

Quote from: Matthew

I doubt it's a DNS issue if you've used Googles DNS and you've had the same issue. Can you try a reset of the router? I've made some remote changes which may help.

Got back to my flat and everything is working beautifully now. Thankyou!

[#5]

Glad to hear things are better.
Let us know if you have any further issues.