How should I respond to this return request?

Hoenir

Don't engage and start a conversation. 

GrubbyGirl_2

I wouldn't reply and block him from buying anything from you in case he starts playing games

martindow

I think I would reply as GadgetGuru has suggested as it seems impolite to not respond at all.  They will probably be expecting no as an answer anyway, but suggesting going to the manufacturer looks helpful.  I would also then block them as a buyer in case they carry on the correspondence or try to seek retribution in some way.

GadgetGuru

Thanks guys - have already added the buyer to my blocked list just in case!
Doe this block messages etc as well, or just block the ability for them to purchase any of your items?

Belenus

GrubbyGirl_2 said:

I wouldn't reply and block him from buying anything from you in case he starts playing games

I would reply along the lines the OP wrote above.

Ignoring and not replying is more likely to prompt 'playing games' than a politely worded explanation of the reasons for refusing a return and a referral to Intel.

I would also block as the OP has already done.

GadgetGuru

Yeh i agree. 
I have responded with:

Hi,
Many thanks for your message.
I am sorry you are having trouble with your item, although as this is an item purchased almost 1.5 years ago it falls outside of the eBay returns window.
Hopefully Intel may be able to help you further. 
Sorry I couldn't be of more help.
Kind regards

I'm sure I will get a dissatisfied response, with threats of further action etc, although I won't respond to anything further.....

Money_Grabber13579

I had something similar a few years ago and I just ignored it. Never heard anything more. In my case, it was a very shouty message (in capitals), demanding a full refund and saying that I’d caused him all sorts of inconvenience. Also accused me of fraud because the listing was no longer there (eBay delete them after 90 days I think?) It’s never going to be possible to reason with someone like that so was happy to just ignore.

GadgetGuru

Its been 2 days and not head any reply - but not sure if thats because he is blocked (I thought blocking someone just ended their ability to purchase, not from contacting you also....).
Anyways, I've drawn a line under it
Thanks