To answer this question we have to split this Topic first.

Before you start decide which method you want to use. RUP wouldn't be a glad choice because you probably want to hide your result so you can't invite other user in to the development process who have different ownerships. This would give a lot of overhead in this project.
Simon says: "Learn which development tool fits best."

Next:
1. Using a computer.
This is difficult, maybe you'll learn if you grow up. For the beginning we recommend Windows XP, if you´ve any Problems, you could ask your Friends to help - nearly everyone use it.

2. Make a Website to spread the virus.
This is a very complicate task. First, you have to decide what programming language you want to use and if there are different technologies in use. For example: html, php, asp, Java, JavaScript.

Which tools you want to use to develop, maybe you need a cvs, or a project management.

Keep in mind that you have to communicate with other team members and that you have to do documentation. I would recommend Microsoft Project Server 2003 and Outlook 2003 with Share point Services for that.

Your SDK should have a good work flow, and flexible in use with other tools. At this point Microsoft .NET Framework SDK is your Choice.

A Server to deploy your website could be Apache, and depending on what technologies you are using Cocoon, Tomcat, Mysql or PHP5 ? Or you decide to be strictly homogeneously . Once you set up Project Server and Share Point Services , IIS is already running. So why should you use another server. Microsoft IIS will do fine.

To finish your project right in Time you should use a Network that is stable and easy to administrate. That keeps you in touch with other developers with focus on the time line. To round up your documentation Microsoft Office becomes handy. With PowerPoint you have the ability to show others what you did, how and why with a few clicks.

The Website which deploys the key logger could be done in a few minutes with MS FrontPage. If you don't want to infect your own system you could use MS Virtual PC as a Sandbox.

Summary:

My recommended development environment
IIS, SQL 2000 SP4, Share point Services, Project Server 2003, Outlook Exchange, Office 2003, FrontPage, MS .Net Frameworks SDK, Virtual PC 2004, Windows 2003 (DomainServer), Windows XP prof (Workstations)

I hope all this arguments are enough to show why you should use a MS development environment. But the strongest Argument to make it real, that you have to use it is:

If you use Microsoft for this project, I guarantee that it will be a success.

At least because there are enough bugs you could use to exploit.