Access to broadband but cannot access email or web pages

[#1]

Hi,
something strnage going on with my system at home over the last week. Suspected it was a faulty router at first, but as I had a spare one to try, I no longer think the fault was there.
Basically, I keep losing access to the internet and email. I've logged onto my PLUSNET router which shows I'm connected to everyhting. I can see their DNS servers listed.
If I try to perform a nslookup against say www.bbc.co.uk , my PC cannot resolve the name. If I do this against the DNS servers, all is OK. HOwever, I cannot display at webpage via domain name. ( not tried by IP...)
If I check my IP settings on my PC, I have my router listed as DNS , so all should work.
I am using  HOMEPLUGS to connect IP via power-lines in the house, and am suspecting this is the issue. Having switched off the one near my PC and switched on again, all appears to start working again.
Anyone have such issues?

[#2]

When your network is in the faulty state, can you access your router's web pages, via your powerline adaptors ?
What does your powerline adaptor's network view say is happening when in the faulty state, and do all the plugs show green lights ?

[#3]

TP LINK AV500 Powerlines ?

[#4]

Hi,
I had forgotten about the power packet utility that I had. Never thought of looking at that . If the problem happens again, will check their status. However, I'v now swapped it for the one I use on my Smart TV. So far the PC connection is OK. thanks for the suggestion. Also, they are Home Plugs from SOLWISE.
Thanks