Setting up an IIS web server is peanuts and although you do expose your PC to the hostility of the internet (what with all those trojan writers, script kiddies, etc.), you can make it happen. Everyone started somewhere - even the gurus out there started with baby steps and learnt the hard way!
So, with that said, if you are using a spare PC that will have no valuable/strictly confidential data, then all you need do is make an image after everything is working. Should you be compromised, all you have to do is re-image. Of course, you'd have to perform backups of you data which you can then restore after re-imaging.
On the other hand, if you only have one PC, then you'd be better served by installing some virtualizing software - something like VMware or Virtual PC - I've never used VPC. Should your system be vandalized, all you have to do is revert to a saved snapshot. This is what I've done and although I religiously keep up with all the patches that M$ releases, I've been hit once. But with the snapshot, I was back up and running in under 1 minute.
I've since then made my system redundant and I've daisy chained 2 IIS webserver. Visitors hit my IIS5 server hosted on Windows 2000 server, which gets pages from IIS6 running on Windows Server 2003. I also have a DNS server hosted on Windows 2000 with a local domain which I haven't registered yet. These 3 OS's are virtualized by VMware running on a Windows XP Pro host.
I'm now di.king around with Apache, PHP, MySQL and I'm about ready to delve into it. And guess what, VMware can host a virtualized guest linux system, yippee! Oops, is my immaturity showing through?
For VMware to function just right, you need plenty of horse power. I'm running an AMD 2600+ XP processor, 1.5GB RAM, 180 GB harddrive but I'm limited by my ISP - 256Kbps down/64 Kbps up - meaning web surfers on my site get data back at 64Kbps - dang it! I sometimes see performance degradation whenever too many people hit my server at once - like when I posted my wedding photos and sent an email out to ~150 people - what a dumb ass!
More power to you as you embark on the journey where many before you have gone and might I add, conqured!
Excuses are like assholes. Everyone's got one and they stink to high heaven!