Frontrec, not much in your log. However there are a few things that need fixed.
Open HJT , scan and have HJT fix the following:

O2 - BHO: (no name) - {5C8B2A36-3DB1-42A4-A3CB-D426709BBFEB} - (no file)
O2 - BHO: (no name) - {FDD3B846-8D59-4ffb-8758-209B6AD74ACC} - (no file)
O3 - Toolbar: (no name) - {BA52B914-B692-46c4-B683-905236F6F655} - (no file)
O9 - Extra button: (no name) - {CD67F990-D8E9-11d2-98FE-00C0F0318AFE} - (no file)
O16 - DPF: {4ED9DDF0-7479-4BBE-9335-5A1EDB1D8A21} - http://download.av.aolsvc.co.uk/molb...,84/mcinsctl.c ab
O16 - DPF: {BCC0FF27-31D9-4614-A68E-C18E1ADA4389} - http://download.av.aolsvc.co.uk/molb...21/mcgdmgr.cab

Using programs like Reg Fix will only make matters worse. There is no good third party registry cleaner.

If you are not affraid to format then by all means do so. I always suggest a format and reinstall every 2-3 years anyhow. And with you using the reg cleaner(s) chances your system files are pooched.
If you want to try a Repair Install first this may help. What a Repair does is replaces and files that may be missing or corrupt right over top the existing install. However, Before you perform a repair installation of Windows XP, you must uninstall Internet Explorer 7. If you do not uninstall Internet Explorer 7 in this situation, Internet Explorer will no longer work after the repair installation is completed. Specifically, the repair installation does not restore earlier versions of the files in the Program Files\Internet Explorer folder. Therefore, the Internet Explorer 7 files will be incompatible with the Internet Explorer 6 files that are installed in the Windows\System32 folder.
How to perform a repair installation of Windows XP if Internet Explorer 7 is installed

Configure your computer to start from the CD-ROM drive. Then insert your Windows XP Setup CD, and restart your computer.

1.When the Press any key to boot from CD message is displayed on your screen, press a key to start your computer from the Windows XP CD.

2.Press ENTER when you see the message To setup Windows XP now, and then press ENTER displayed on the Welcome to Setup screen.

3.Do not choose the option to press R to use the Recovery Console.

4.In the Windows XP Licensing Agreement, press F8 to agree to the license agreement.

5.Make sure that your current installation of Windows XP is selected in the box, and then press R to repair Windows XP.

6.Follow the instructions on the screen to complete Setup.

Hi.

Thanks again. The thing seems a little better, but the main problems remain. I'm not sure I'm confident enough to do the Repair job, I'll likely wait until the wekend when offspring may be able to attend!

My main bugbear is why I can't get my Nokia PC Suite software to work, as I've got photos on the handset that I want to transfer to PC. I've just reinstalled the latest version again and still no joy. Looking at Device manager, there are two yellow question marks, one marked other devices and one marked Nokia N73 and if I double click on that it tells me "This device is not configured correctly. (Code 1)
To reinstall the drivers for this device, click Reinstall Driver", which just leads to more complications. I know there is a fix for this, can anyone help?

Thanks.

This usually means the device has no drivers installed or is incorrectly configured.

Why? Do you not have the driver cd to place in the cd-rom when prompted?
Nokia - Modem drivers - PC software - Nokia N73 Music Edition - Product support - Get support and software