IIS 6, dynamic ASP pages, slows down with 10+ users, CPU too high ?

We have a IIS 6 Win2K3 Server.  Nice new Dell Poweredge, good 3.0 dual core Intel processor, 2GB memory, etc.  We have one website with just a few .asp pages. vbScript is the default, mostly server-side, some client-side, good use of client side cookies (variables) with zero use of session variables.   Our website is very dynamic in nature since each internet visitor is getting a unique 'survey', a series of pages individually crafted on the fly.    Our CPU starts to run at 90%+ after about the 10th concurrent visitor, and slows the page to page response to a crawl for everyone.  It's not the bandwidth, not the NIC, or memory.  A look at Task manager shows the high CPU process w3wp.exe.   Even one visitor, we see CPU spike at 50% for a split second.    

We investigated .net (.aspx) pages, but the big bang there is mostly caching performance, which really does little for us, since no two pages are alike.   Our testing of some .aspx converted files/functions even caused CPU 90% with even fewer visitors.  We're not sure if .aspx is worth our attention, at least for now while we're looking for a quicker speed fix.

We investigated our website application itself, looking for obvious design flaws.  Then we tried a simple asp test that produced a bunch of dymanic text, and saw that this page also caused high CPU.  This leads us to believe that the ASP engine (if I'm saying that right) is generally slow under stress on our server.

We investigated VB DLL Com, but saw similar results.

We investigated the IIS 6.0 App Pools, but that does not apply since we only have one website.

We investigated the Web Garden, and Worker Processes.  We read a few help sites that said to leave this alone, ie leave settings at one worker process.  Therefore we are hesitent to mess with this area.

At this point, we're not sure what to do.  We anticipate a occasional max of about 50 or 100 concurrent visitors.   My common sense would normally tell me that 50, or even just 10 visitors, should not bog down  the server/cpu, but it's happening.

I don't know where to look next.     I know that whatever our next steps will be, they'll be time consuming, so I'm hoping to get some help on what direction to go which hopefully leads to better  performance on the server.     Help.