I was contacted by someone claiming to call from Microsoft alerting me to errors occuring on my computer. I was stupidly taken in and gave them the id number from the software so that they could remove the problem. I am now worried that this will allow them access to my computer and possibly to information like banking details etc. Is this possible? He removed the icons from the screen, made the screen go blank and told me he had wiped it clean and I wouldn't be able to use it, unless I allowed him to put some software on and pay him £35. I switched off the computer at this point. Has giving them the id no. made me vulnerable?