Every day of the week virus, spyware, and adware creators come up with new, ingenious ways to gain access to your PC. These simple pointers will help keep the hackers at bay:

Stop and think before you click: Downloaded files that end with .exe, .com, .bat, and .scr, (also files with .doc and .xls extensions), can render your computer completely useless with a single click. Many e-mail programs block access to any attachments so take the extra time and think for a few seconds before you decide to open it or not.

Use an anti-spam filter: Most viruses and spyware are installed by various methods of Internet browser hijacking however, e-mail is still a very common source. Use of a junk-mail filter will significantly reduce the likelihood of running harmful scripts contained within messages.

Keep your antivirus software up to date: Using antivirus software that has expired past it's subscription period is definitely not an option: Not only do you lack the crucial virus database updates, but you expose your system to malware that targets known flaws in antivirus software.

Prevention against WORMS and Viruses: Install antivirus software, update regularly, and use it regularly. Never open unsolicited e-mail attachments with the file extensions VBS, SHS, or PIF.Disconnect your network or modem cable when you are not using your computer.

Antivirus software is software that is installed on your computer that protects you from viruses. Antivirus software programs contain in the region of 40,000 - 100,000 "malicious software definitions" that are updated on a daily or as needed basis.

I highly recommend Grisoft AVG Anti-Virus (Free) for antivirus protection.

If in doubt try online: You should only install and use one single antivirus program at a time on your computer because multiple antivirus programs will conflict with one another and cause your computer to completely grind to a halt. If you have any doubt about your antivirus program's effectiveness, you can use a free online virus scanner, such as Panda Software's ActiveScan) or Trend Micros HouseCall.

Download with care: Any program you download and run on your computer system could potentially result in spyware or virus infection. Download software only from reputable online sources that guarantee that all software is free from malicious software.

Use a two-way firewall: Windows XP and Vista each come with a firewall that blocks unwanted or unexpected incoming traffic; it is enabled by default in Windows XP Service Pack 2 and later. However for the best protection possible, you will also want to block unwanted outgoing connections made by spyware, viruses and scripts on your PC that attempts to either connect to a remote server or send out spam.

Windows Vista's firewall does have that fucntionality, but configuring it is not entirely simple enough for the average Windows user. Instead, you can get one of several free bidirectional firewall programs, such as Zone Labs ZoneAlarm Free, or Agnitums Outpost Firewall Free.

Make use of antispyware program: Anyone who uses a computer can succumb to spyware infection. In fact, 9 out of 10 Internet-connected PCs are infected with some kind of virus. Spyware can be any application that tracks your online or offline PC activity, serves you adverts, redirects your pages and bombards you with pop-ups. If you use the Internet, its possible that some form of virus threats are already active at work on your PC system.

Spyware can ocassionally go unnoticed however, it is more likely that you will notice that it is present on your computer system due to the obvious symptoms that your computer may experience. It is EXTREMELY difficult to get rid of but not entirely impossible.

Even if you suspect you have successfully removed an unwanted program manually, a remaining dormant file can trigger a complete reinstallation the next time you restart your computer. And as a survival tactic, spyware programs often leave similar traces elsewhere on your system so you can often never eliminate it completely after only one attempt.

Spyware, adware, and some scripts / trojans slow down your system, cause crashes, and track your online activity. Antispyware utilities work much like antivirus software, detecting and removing the unwanted software from your PC.

One free tactic you can employ is to upgrade from Windows XP: As Microsoft service Pack 2 makes Windows XP much safer, although the operating system still has many security flaws which can be exploited, and it remains prime target for spyware creators.

If you still have a slow PC after trying the software above and you think it may be due to spyware, you can find more help and information on fixing your slow computer at Slow Computer Help.