Internet Explorer can't display the web page after Products are added.

Please help .... I can navigate the page options, but after adding a product or enter configuration settings or anything that has to be written to the database it takes a great while to process and eventually tell me that "Internet Explorer can't display the web page - I am using a LocalHost.
I cleaned the cache and that of Internet Explorer as well - This ERROR happens with all versions of NopCommerce (with source or without) - I even installed NopCommerce with and without sample products - It gets very slow - sometimes it shows the first page and other times it shows a messed-up page or nothing at all -
I am running this on Vista and used IE 32 and 64 bit - I am running .Net 2.00 and 3.5 - SQL Express 2005 - The database looks OK, But I was only able to enter a few categories and since then nothing works - I did a great number of re-installations, but...... - Could .NET 2.00 and 3.5 have something to do with this - Or could Internet Explorer - But I can run Mangement Studio and Navigate other URLs  and Visual Web Developper 2008 Express don't show any Issues - I NEED HELP.... any SUGGESTION   -- Waiting Anxiously.  Thanks.

Does anything get written to the database? Maybe the databse user doesn't have enough access.  Try giving the user dbowner permissions.

Hope you can help -

I went to my first install and saw the old categories I originally created, but could not add any products - "Internet explorer can't display that page -
I created a sub-directory from the root and install NopCommerce with sample data - I saw the default products on the page, but I experienced the same error.
I created a new folder in the localhost directory and install NopCommerce without the sample data - I tried creating a category and got the same error -

I made sure all those folders and subfolders have administrator rights (all the permissions)- I made sure that Every accounts for that folder has all the rights - (Excep for CREATOR OWNER for which no rights can be assigned to, nothing will be accepted) - The default website has multiple protocols (IIS 2.0 and 3.5)

I checked IIS and had to place that folder in the Application Pools and could only assign "ApplicationPoolIdentity" where the others have "NetworkService" or local system - The applicationPool itself has"NetworkService"
And prior to that, I thought  IIS had an issue because I could not see "windows Authentication" on the list. So I repaired the installation - Later on, I learned that it is OK without Windows Authentication being on the list.
And prior to that when I made the folder and application folder - testing the authentication "Pass-through authentication"(defaultapppool:networkService)  Works, butCannot verify access to path (C:\inetpub\wwwroot\....)

Awaiting your reply.

I forgot to mention that CREATOR OWNER has "Special permission"

I know you can HELP me with this.  --- Please help.

AFter attempting so many different things - I noticed that I can always create CATEGORIES at first, but not the products afterwards. -
I ran version 1.1 - and was able to create 2 Categories and it failed after trying to create the second product.

I checked the database and saw the categories and the products there, but when I checked the code, it passed -
when I ran the code,   HERE the ERROR message that I get.


Msg 2714, Level 16, State 6, Line 1
There is already an object named 'Nop_Category' in the database.
Msg 2714, Level 16, State 4, Line 1
There is already an object named 'FK_Nop_Category_Nop_CategoryTemplate' in the database.
Msg 1750, Level 16, State 0, Line 1
Could not create constraint. See previous errors.

and the other.

Msg 2714, Level 16, State 6, Line 1
There is already an object named 'Nop_Product' in the database.
Msg 2714, Level 16, State 4, Line 1
There is already an object named 'FK_Nop_Product_Nop_ProductTemplate' in the database.
Msg 1750, Level 16, State 0, Line 1
Could not create constraint. See previous errors.
Msg 2714, Level 16, State 4, Line 1
There is already an object named 'FK_Nop_Product_Nop_ProductType' in the database.
Msg 1750, Level 16, State 0, Line 1
Could not create constraint. See previous errors.