Q: I have a Pentium III 450Mhz computer running Windows NT. I have just bought a USB scanner for my computer but, no matter what I do, I cannot get the computer to recognise it.

A: For those readers unfamiliar with USB (Universal Serial Bus), this is a relatively new way of connecting peripherals, such as scanners etc., to your PC.

Essentially, it is just another connection in the back of the computer. The problem with the scanner not working is that Windows NT currently (and it looks set to remain that way) has no support for USB devices.

If you want to use USB, you will need to upgrade to Windows 2000 or install Windows 98.

Q: I have often been told that I should always shut down windows before turning my computer off, but I have never really understood why. Can you explain?

A: When you use your computer, it stores information in the computer memory, or RAM. Unlike hard disk storage, RAM is "volatile", which means that, without a continuous power supply, the information is lost.

When you shut down the computer, all programs are closed and data in the computers memory is stored safely on the hard disk (which still retains data even if the power is turned off).

Windows (and indeed many applications) also create many temporary files. When Windows shuts down, these files are removed. If this does not happen, these files can build up on your machine, taking up many megabytes of space.

Q: Can you suggest a really good internet PC support site?

A: There are many sites that provide helpful information for computing beginners but very few that have good coverage and depth. One site I am particularly impressed by is PC911 (http://www. pcnineoneone.com) who have a really exceptional set of articles covering every aspect of PC maintenance and repair. Their "how to" section is particularly good. Another good site is http:// pcsupport.about.com/. Although not quite as thorough as PC911, it is still a very useful site for the beginner.

Q: How do I send a file with an email?

A: Many people do not realise that emails can not only contain text but can also have a file attached to them.

It is worth noting that email is not a good transport mechanism for very large files because it is relatively inefficient. Many free email providers will not allow attachments over 1MB in size. To add a file to an email in Outlook, simply open Windows Explorer, find the file you want to send and drag it into the email window. Different email packages have different ways of dealing with this.

Look for anything that refers to inserting a file or attachment.