I use yahoo mail and, when I went into my inbox this morning, the first line said cupid.com - sponsored. I don't know how this got onto my computer but, when I tried to download a free version of AVG security, it installed something else, which I didn't want, and couldn't get rid of, so did a system restore. I am also getting adverts on other pages. Any ideas? Now it is advertising facebook.

Did you have any Internet security programmes installed before this started happening? If the answer is no, then why not? It looks like you have a malware infection. Get yourself a decent 'paid for' security programe and then run a scan to get rid of the malware.
In the meantime try the free version of 'Malwarebytes' to try and get rid of your problem.
https://www.malwarebytes.org/free/

I think it's always best to exhaust all possible solutions before doing a system restore.

Does anyone know why I am receiving these ad choice adverts on every page now? I did used to, but then they stopped. It is incredibly annoying.

The ads are shown depending on your browsing habbits i thought.

i searched chinese food now i get adds for asian dating ...

Use adblocker
https://adblockplus.org

They get shown because of tracking cookies. The tracking cookies on sites track your surfing and then adverts on sites and forums show an advert most of the time about the item that you looked at on a particular site.

I always do. It is meant to be used as a last resort solution. I have never advocated using free anti virus/security software, and was just doing so myself until my paid version arrived. We input too much sensitive information, to allow our security to become compromised.

This has been installed on my computer for the last few months. And the ads which appeared initially, had nothing to do with my browsing history. Now, however, because I shop for my boxers online, I am receiving ads from pet websites, which I don't mind, as it means I get the special offers. If it meant getting rid of the rot, I would lose these willingly. I receive emails from the sites I shop with anyway.