thanks fellas, just downloaded 'malwarebytes' as charlie suggested, if that doesnt work i'll try 'ad block' too
"MalwareBytes Anti-Malware" (MBAM) is a package which is designed to remove an assortment of modifications which may have been made to a Windows machine. Some of the modifications may have been made deliberately by the user and might come under the heading of ill-advised. Most however will have been made without the user's knowledge or permission. MBAM can scan data to look for suspicious patterns within it which might indicate malicious software on the machine. Generally speaking, it is targeted at removing malicious software and at finding and fixing unauthorized changes, hopefully preventing the abuse of the computers. It's pretty good at its job and I use it a lot on customers' machines. I don't need it on my own machines, as they don't run Windows.
MBAM can also look for things like changes to the settings which tell the computer what programs to load when it starts up; what to do when it is asked to 'open' a file; or to find a resource on the Internet; or generally what to do when the computer's user does almost anything at all with the keyboard, mouse or whatever. Many of these settings can, without the computer user's knowledge, be subverted by unscrupulous people for example to send your passwords to some server in China (I've seen that happening on a customer's machine); or to send mail, unknown to you; or to attack other computers; or to take your browser somewhere other than where you wanted it to go, usually to advertise things to you. It's particularly easy for the criminals if you don't keep up to date with security patches; or if you use certain versions of Windows or Internet Explorer; or many of a whole bunch of other programs infamous for security problems such as Adobe Acrobat and Flash Player.
http://www.qualys.com/research/top10/
Although abusing computers in this way is what we call computer crime, at least in the UK, from where I'm sitting it seems that law enforcement in this area is basically non-existent. On occasion, when I've found evidence of criminality, I've tried really hard to get the police to take action. Usually they've done nothing, mostly because of jurisdictional problems or the rules of evidence. If a criminal from Uganda, Belarus or Argentina takes over your PC and then cleans out your bank account, as far as I can tell you're on your own. That's not to belittle the work of the Met's Hi-tech Crime Unit, but the six hundred cases a week that they can ewven look at is barely scratching the surface.
The advertising that you're seeing, Steve, SHOULD just be the result of the browser doing what it's legitimately been told to do, and in that case I should not expect that MBAM would make much difference to any advertising that you see. Some browsers have facilities to avoid the more intrusive online advertising. I find that the ad-blocking 'addon' for Firefox is pretty good. If this can block the adverts, and MBAM finds nothing suspicious, all is probably well. The advertising definitely should NOT be the result of modifications made to your computer, without your permission, which MBAM can then find and fix.
I've never seen the adverts mentioned in this thread. That may be because of the ad-blocking in my browser, but it may instead be because I don't use Windows.
Which brings me to the Stock Exchange.
The symptoms Steve describes need clarification, but the similarity with symptoms I've come across before bothers me a little. Some time ago, criminals discovered that they could dupe otherwise perfectly upstanding advertisers into serving malicious data within adverts. The Stock Exchange Website was amongst the most high-profile that I know of to be abused in this way. For at least several months, from late 2010 to early 2011, it was serving malicious data which was used by criminals to 'take over' PCs when they were used to browse the Stock Exchange Website.
http://www.bbc.co.uk/news/technology-12597819
It beggars belief that an organization like the Stock Exchange could permit such a thing at all, let alone manage to avoid noticing it for so long, even while Google was listing the LSE Website as malicious! If organizations with fewer resources than the LSE take on the responsibility of serving third-party data, on the fly, from their own Websites you can imagine how difficult it is for them to protect themselves and their users against this sort of threat. Personally, I think the whole idea is insane and I would never do it, but the financial rewards are attractive and it's easy to see how a salesman could gloss over the risks while closing a deal with a Website owner. This kind of advertising practice is very widespread.
I have no evidence that BCUK has suffered in the same way as the LSE. But if MBAM does in fact prevent advertising which appears as a direct result of browsing BCUK, then if I were Tony I'd want to investigate. It might indicate (at the very least) dubious practice such as modifying browser settings without the user's consent.