Lopped off
I recently visited a site that claimed to have free MP3 files, but in fact seems to have inserted a cookie somewhere in the set-up files of my computer. Every time I restart, it sets the internet home page to wfix.com and then appends the proper address to the end. It also adds a toolbar to adult, gambling and other unwelcome sites. Caroline Brown

Jack Schofield replies:
You have fallen victim to a widely hated piece of scumware usually known as Lop.com (for Live Online Portal), though it also appears under more than 40 other names from aavc.com to wflu.com. It can usually be removed by Spybot Search & Destroy software, which you can download free from http://security.kolla.de. For more details of Lop.com, see www.doxdesk.com/parasite/lop.html and www.spywareinfo.com/articles/lop.

Also, go to the security section of your browser - Tools|Internet Options| Security in Internet Explorer - and make sure it is not set to Low. If you have a Custom Level setting, you can change the settings for Active X controls are set to Prompt or Disable. With the Prompt setting, websites will find it harder to install this kind of parasite without asking - though you may well have been asked in this case, too. A quick visit to Doxdesk's parasite page will automatically detect common parasites that may be installed in your browser but, ironically, it uses an Active X control to do this.

NewDotNet
When I start Windows, a message appears saying: "error loading c:\PROGRA ~1\NEWDOT~1\NEWDOT~1.DLL - the system cannot find the path specified". I think it may have been caused through accidentally deleting a .dll file, and it seems to affect my Internet Explorer program, as it cannot find any servers. Mark Oldham

JS: You have become the victim of a another common piece of scumware, NewDotNet. This Internet Explorer plug-in changes the way your DNS (Domain Name System) works so that it can access internet addresses that are not official top level domains. NewDotNet's "new domains" include .shop, .xxx and .mp3 addresses. If the software is not removed correctly, you can lose access to proper domains such as .com, .net etc. Both Spybot and Ad-aware 6 can remove NewDotNet. For further information, see www.doxdesk.com/parasite/NewDotNet.html, www.cexx.org/newnet.htm and the Microsoft Knowledge Base article Q302463.

The NewDotNet site also has removal instructions. At various times, NewDotNet has been distributed with numerous applications including BearShare, iMesh, KaZaA and Go!Zilla. When installing these and similar free applications, watch the options to make sure you do not unintentionally install NewDotNet, Comet Cursor, Gator, Lop, TopText, WebHancer and similar parasites.

Any port?
Reading about internet security, I often come across advice to close particular ports. What are they? Sam Nasralla

JS: In this case, a port is just the end-point of a logical channel or connection that is made between software running on your computer and software running on another computer. Many ports are assigned to specific applications. For example, HTTP, the protocol used to carry web pages, uses port 80. Andrew Daviel has a web page at http://andrew.triumf.ca/cgi-bin/port where you can type in a port number and find out which applications use it. However, some file-sharing applications are now using a port-hopping technique to make it harder for ISPs and others to stop them from working by blocking specific ports. Robert Graham also has an excellent but technical FAQ (list of frequently asked questions) about the various ports at www.robertgraham.com/pubs/firewall-seen.html.

If you run a firewall such as Zone Alarm or Sygate Personal Firewall, this will help you understand what it is telling you. Bear in mind that computers often send messages to one another: it doesn't necessarily mean someone is out to hack you.

No games
How can I delete or disable Freecell, Winmine etc from Windows 2000? When I try deleting them from System32 in WinNT, they reconstitute themselves within minutes. Andy Northedge

JS: Recent versions of Windows try to protect and replace their files, because users have been known to delete essential files. The real problem is that the games - and several other components of Windows - have been made invisible to the Add/Remove Programs applet, so you cannot uninstall them. In Windows 2000 and XP, you can make them visible by changing the sysoc.inf file. For an account of the process, see www.cdc.state.ca.us and www.winsupersite.com.

Pictures
There are eight .jpg files associated with Windows Me stored in the folder My Pictures (cliff in clouds, diagonal sand, etc). I've tried deleting these, but they keep returning quite quickly. John G Griffiths

JS: Curious as it may seem, these wallpaper backgrounds are also part of the Windows operating system and are therefore protected by the PC Health feature, System Restore. Since they are harmless and take up a negligible amount of disk space, I'd ignore them.

Backchat
· Keith Arrowsmith wanted a UK-oriented replacement for My BBC, a news service that allowed users to select subjects from pre-defined panels, until it was discontinued. I suggested Yahoo and News2you, and appealed for advice. Alan Pagett responded: "News junkies can do worse than try the newspaper reading-room at the Internet Public Library." Chris Pogson favoured www.thebigproject.co.uk , saying: "If they don't have a link available, then tell them and they'll add it." Ed Hynes from Pennsylvania, USA, suggests www.refdesk.com as being "content-rich and easy to use". All have merits, but Yahoo News still looks like the closest alternative to My BBC.