A firewall does nothing to prevent infection from viri/worms. And most firewalls can be defeated by an experienced hacker. ALL a firewall does is watch specific ports (there are 65535 for each interface) and allow/block applications from communicating on them or hackers scanning them from opening them for R/W. Lots of worms and virii manipulate firewalls to allow an app to "talk" on a specific port. Most do this above the physical network layer, routers being the exception, so are easy to defeat by...someone like me. lol

Is it dll.vbs?! The 'Surprise' e-mail bug? Haven't seen that one in years! Suppose it is probably a variant.

I've not seen one with Surprise in it since about 1990. The easiest way to prevent viruses/worms from getting into your system is to stay logged in under restricted user rights. NOT Administrator.

Virii and worms always operate under the context of the logged in user. If you surf with an account that does not have rights to change system/startup files, and you don't open infected files under an account that has system rights, then you will never get infected.

Of cource a good antivirus/antimalware program and regularly checking what is loaded at startup, and disallowing BHOs in your browser is always good in addition to the then good sense reccomendation of never opening attachments and never clicking OK on a modal dialog box that pops up while surfing. ALT-F4 it, don't even press close because the buttons are defined by the programmer and there can be code attached to the OnClose and BeforeClose events for that dialog that fre when the X is pressed.