In the UK and elsewhere, scammers - usually calling from the Asian sub-continent - continue to catch out the unwary, hitting them for money, stealing their credit-card details and infecting their PCs into the bargain .

That's not surprising, though, when a huge number of people simply do not understand that it is impossible for anyone who calls them up to know whether or not their computers are infected.

Below is an edited extract from an email I sent this week to a client whom (I later learned) just pulled back from the brink and refused to allow a scammer to take remote control of her computer.

Other clients (all men, oddly) have been less fortunate and have ended up with infected PCs; compromised credit cards, ID and internet security; and substantial bills to put right the damage caused by these fraudsters, plus a whole lot of inconvenience.

I phoned your home as soon as I got your email and left a message asking you to call me BEFORE you use your computer!

That's because, sadly, the 'company' that called you up is bogus - this is a long-running scam that has been going for over two years and is widely reported on traditional media and also on highly-respected sites, including the BBC and The Guardian.

Here is a forum thread on moneysavingexpert that also makes interesting reading and below are some links on techie sites about this type of fraud:

http://www.pcpro.co.uk/news/security/359233/the-unstoppable-tech-support-scam

http://www.theregister.co.uk/2009/04/10/supportonclick_scareware_scam/

http://www.digitaltoast.co.uk/supportonclick-systemrecure-scam

http://forums.whirlpool.net.au/archive/1200200

There are call-centres full of people making these fraudulent phone calls and they are raking in huge amounts of money - from the infections that they put on PCs (some of which can compromise your online shopping and banking) and from the folks who get conned and cough up money, divulging their credit-card details [to fix problems that the baddies themselves have introduced!].

If, as appears to be the case, you allowed them access to your PC, please switch if off without using it any further and bring it to me so I can disinfect it and undo any other damage they may have caused.

But whatever you do, PLEASE call me asap and immediately stop using the PC if you did let the scammers connect to it.

The bottom-line here, of course, is that you shouldn't trust cold-callers on the phone when, almost certainly, you wouldn't trust them at your front door (and, hopefully, not in email, either) .

Trouble is, too many supposedly reputable companies, including banks, do the most stupid things. My own bank cold-calls me and demands security details (yes, it really does).

And I was far from impressed when it recently added a 'remember' me option to its ebanking site!

So, it's hardly surprising that people don't always have their guard up and, thus, can easily get ensnared by smooth-talking fraudsters. Most know little about computers because, understandably in my view, they regard them as tools, not things to worship as some of us techies do.

The office phone rang this morning (Sunday) at 8:45am but, although I guess it might have been important (to the person calling), I was still in bed and (bad man that I am) ignored it - I'd been working until 3am carrying out various tests** on Windows 7 Professional running on a Samsung NC10 netbook.

At a rather more civilised hour, the same person called back, explaining his problem.

He'd come down from university to visit his parents, bringing with him a bent copy of Windows 7 Ultimate.

He then proceeded to bugger up both of his parents' PCs, such that they don't work. Trouble is, there's some important stuff on there (data, rather than operating systems or programs, as I understand it).

He says he's bringing one of the PCs round at 1pm and I've agreed to save any data that might still be there and do a fresh install of Windows 7 Home Premium from a kosher installation DVD - but without activating the operating system.

He can then buy a student copy of Windows 7 Upgrade (it's only £30 for students) and do the activating himself.

He'll have 30 days in which to do that, because you can run Windows 7 for that amount of time before it must be activated.

In case you missed the link above, the place to go to buy your student copy of Windows 7 is here. Know that it IS possible with this offer to buy one copy of Win 7 Home Premium (32-bit or 64-bit) AND one copy of Win 7 Pro (32-bit or 64-bit).

If you are not a student, check out this amusing story on HEXUS.channel about the student deal.

I'll report back, of course, on how I get on with the data-recovery and Win 7 install on the crocked PC that's due to arrive here soon.

** Oh, and those tests on Windows 7 Pro showed pretty much what I thought I knew already - the OS works just fine on the little netbook but the Pro version is badly ham-strung in one particular regard by the Samsung NC10's rather limited hardware, so there's no point opting for Pro on the Samsung netbook if you want to use its XP Mode - it doesn't work.

(If you want to run Win 7 on a Samsung NC10 (or other netbook), check out the Win 7 area on this independent Samsung netbook support forum for tips and hints)

Also see this link to compare the features of the different versions of Windows 7.

XP Mode is designed to use a virtual-PC program (which emulates a complete computer) to let you run a free (Microsoft-supplied) special copy of Windows XP WITHIN Win 7. The idea is that this will let you run any programs that did run under XP but don't run under Windows 7.

Bob