This is a bitty question and I'm not 100% sure it's in the right place, sorry if not.

My mum had an error come up on her computer a couple of days ago and she reckoned it was the standard Microsoft "An error has occurred" with the option to "send error report" which (as she thought it looked serious) she did. The box went away and she thought nothing of it.

Today she got a phonecall from a company called "Online PC Hub" who called and told her that they had received her error report and were calling to sort the problem out. The guy she originally spoke to put her through to his "technician" who talked her through giving him the IP address for the computer and then accessed their computer remotely. She said that she could see various windows coming up, including Norton antivirus and a bunch of "scanning" pages saying that she had a certain number of "critical errors" and spyware, malware etc, all of which the "technician" told her he had corrected. During the course of this a couple of boxes came up on the screen which mum said looked like the ones you get (with the progress meter) when you're installing software but she asked the guy what was being installed and he reckoned nothing was.

Once the phonecall was finished the guy on the phone told her that the support she had received was "free" but next time she would need to pay a subscription, either £85 for the year or she could just pay £29 for this call. She reminded him that he'd just told her (and all the stuff on the computer had said) that the service was free and therefore she wasn't paying him anything, but he insisted saying that she couldn't "expect something for nothing" so to get him off the phone she told him that if he wanted any money he'd have to call back and speak to her husband, and hung up.

She called me at work (or tried) but when she picked up the house phone to call me the guy was still on the line so she hung up and called me from her mobile. I've told her to unplug the modem and my Mister is going to call tonight and remotely check that everything is fine before talking them through turning off the option to allow remote access.

Ok, that's the backstory. My questions to everyone...
This Online PC Hub place seems to be a company you go to if you want to sign up for their support service, they don't appear to have any affiliation with Microsoft at all so why would they call regarding an error report that was sent to Microsoft? Is it possible that they have created a pop-up window which looks just like a MS error window to get suckers who don't know any better to click on it and give them an excuse to call? How did they get my folks number from a clicky box on the web?

Do these things register IP Addresses? If so, should I tell MS that there is a company pretending to be them by making pop-up boxes which look like MS error boxes? Have you ever heard of this kind of thing before? He also told her that she had various problems with the computer and must have installed a version of Norton since we know for a fact that all trace of it was wiped out when Red downloaded the Avast. Also, they had avast which was working fine so where did all this mal and spyware come from? Is it all big scam? Any additional advice/information?

How much data does she have on the machine? And how much hassle would a re-install be, for complete peace of mind? She's probably got a new IP anyhoo, now, if she's been disconnected for a while, just depending on the type of connection and who her ISP is. I'm not so sure where they got her phone number from, though, but I guess that could maybe have been scraped by whatever Malware it was that produced the initial report/sent the initial information.

The company does seem to be legit: http://onlinepchub.com/index.php

I suppose someone can call them and ask what piece of software gave the error message that they rang about.
Did anyone fill out any registration forms when the PC was bought? It could have been outsourced to Online by another company or even where it was purchased from

Sounds like remote assistance is enabled, who did she get the pc from? Some companies may have a system that sends an error report to themselves as well as Microsoft if they can query the stack for error propagation. The way they got the number is if it was registered. Do you know where they got the machine from and who makes it?

They could register IP, but it's not very useful given most people have a dynamic IP. I think the remote assistance works on request/acceptance instead of IP

mal/spyware isn't usually picked up by anti virus software as it is a separate and the scanning heuristics are different as a result. I suggest Spybot Search & Destroy (update when you get it, and also use the immunize function to help stop certain browser exploits) as a good piece of free software. It also includes a tool to notify you when settings are being changed.

Yep remote assistance is enabled, but it won't be for long. They've had the computer for at least the last 10 years and have never registered for any online help or support, when they originally bought the computer they had a guy come round and install all the software, someone my dad knows from work but Dad has enough knowledge now that he's done the upgrades etc since then, they haven't had anyone round (except my Mister) to work on it in at least the last 6 years so it's not something that might have been outsourced on his behalf.

They've never been contacted before and this window that mum clicked on just looked like the regular MS error window "click here to send report" type (you must have seen it) I didn't know that about the spyware not being picked up by anti-virus, but Red will be able to check everything when he gets on there tonight.

The company do look legit but they contacted mum unsolicited and are trying to charge for a free service, but what interested me was how they got hold of my folks number or knew to call given that it was a system problem, not a viral one and so the virus stuff seems to be a ruse. Unless it was a virus which contacted PC Hub, which seems unlikely.

They don't have too much data on the computer (Red has just finished setting them up a back-up onto external hard drive) but it would be a pain for us to go there for a re-install, once the "allow remote access" thingy is turned off then it won't be a problem but she's worried as much about the guy calling back to try and get money out of them since I've reassured her that anything dodgy they've done can be undone (she is convinced they're not legit) but I'm pretty sure she won't be sending error reports anywhere anymore.

They are with Virgin and the computer is some kind of Acer desktop.

Just because the guy claimed to be from PC Hub, doesn't mean that he was. PC Hub might keep a log, perhaps you could call them (from another phone) and ask it it was anything to do with them.