Microsoft
Microsoft Anti-Virus Suggestions
Windows Product Key Viewer (Enables all CD Keys to be viewed prior to format)
Windows Product Update KEY tool
Internet Explorer 7.0 (IE7.0 web browser)
Microsoft Windows Updates (Updates for Windows XP etc.)

Adobe
Adobe Acrobat Reader (Reads PDF Documents)
Adobe Flash Player
Adobe Shockwave Player

Other Useful Applications
FireFox Web browser (Alternative to Internet Explorer)
SpyBot (Spyware)
AVG Virus Scan (Free virus software)
Zone Alarm (Protects PC with firewall software)
Thunderbird Email Client (Alternative to Outlook Express)
PC-Cillin Anti-Virus Software (Anti-Virus software)

Spam Checking
Are you having issues with sending emails, you might be infected by a Trojan...
Find you IP address - WhatsMyIP
Then check the following websites to see if your IP is listed:
Spamhaus
Spamcop