Unsurprisingly, running an online business involves being online for most of the day. One of the constant "joys" that lights up my working days are adware and spyware, annoying little programmes that hijack your computer, change settings and bombard you with "relevant" advertising messages.

There are numerous ways these little blighters can get on to your computer, from picking one up in an e-mail, going to a dodgy website, downloading something off a P2P file sharing network or just from someone unscrupulous on the internet. I seem to pick one or two a week from "typos", when you misspell an internet domain name and end up at a site owned by a cyber-squatter with some nasty code built into their website that instals one of the spyware pieces of software onto your computer.

The implications range from the serious to the ridiculous.

For instance, my father has somehow managed to develop a means of regularly picking up a piece of spyware that blocks his access to the Times Online. Whenever I send him a link to my latest online diary, he replies, "I can't view it again, I've got some piece of crap on my computer that's blocking it."

One of the more serious consequences of the spyware can be applications that tamper with your computer's registry file. This is the most crucial file on your PC and contains the setup of every programme that you have running, where a small change can mean big problems.

One that I've come across was created for quite legitimate means. It makes Internet Explorer, the most commonly used browser on the planet, think it is viewing one website when it is really viewing another. When I'm testing a new feature on my site, I can change the registry file so as to fool my browser into thinking that it is viewing QuickQuid when it's actually viewing a development server. But in the same manner, a simple change to the code could trick my browser into thinking it is viewing my online bank, when it is really logging into a very clever copy hosted somewhere in the middle of China.

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