ContentPlaceHolder Resizing

Resizing is accomplished by resizing adding controls and items to the ContentPlaceHolder. However, if you are using a control like the WizardControl; then size that in pixels large enough to build your forms on.

DIV Align Center

div id="header" style="text-align:center"

Wizard Control SideBar Alignment

SideBarStyle controls the side bar step navigation alignment:

sidebarstyle horizontalalign="Left" verticalalign="Top"

ASPNET 2 Solution File

It seems that the ASPNET 2 .sln file is not required. You can open a site from a folder; save, compile and publish without the solution file.

ReInstall ASP.NET

Try reinstalling ASP.NET on your box using the Administration utility (2.0.50727) to install and uninstall ASP.NET on the local machine.:
Open a command prompt
Stop IIS: iisreset /stop
Change to the .NET Framework 2.0 root directory: C:\winnt\Microsoft.Net\Framework\v2.0.50727Reinstall ASP.NET 2.0 by using the following command: aspnet_regiis -i command.
Start IIS again after it has been run: iisreset /start
Try to access your web page again.