For general computer support, not related directly to your Thunderbird Broadband internet connection, we suggest the following third party resources:
AVG Antivirus - A free, constantly updated antivirus suite for your computer
Ad Aware - A free, constantly updated anti-spyware utility for your computer
A Squared - A free, constantly updated anti-trojan and backdoor utility for your computer
Windows Updates - Microsoft's free security and bug fix update service for Windows