Server Error in '/' Application.

Hi guys, 

Hoping somebody could can help me. The website of the company I work for went down last week and we have been unable to get it working. Most of the pages work but when you try to access the home page I get the following:

Server Error in '/' Application.The remote server returned an error: (404) Not Found.Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Net.WebException: The remote server returned an error: (404) Not Found.

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace: 

[WebException: The remote server returned an error: (404) Not Found.]
System.Net.HttpWebRequest.GetResponse() +5381629
System.Xml.XmlDownloadManager.GetNonFileStream(Uri uri, ICredentials credentials) +69
System.Xml.XmlDownloadManager.GetStream(Uri uri, ICredentials credentials) +3929371
System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn) +54
System.Xml.XmlTextReaderImpl.OpenUrlDelegate(Object xmlResolver) +74
System.Threading.CompressedStack.runTryCode(Object userData) +70
System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) +0
System.Threading.CompressedStack.Run(CompressedStack compressedStack, ContextCallback callback, Object state) +108
System.Xml.XmlTextReaderImpl.OpenUrl() +186
System.Xml.XmlTextReaderImpl.Read() +208
System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean preserveWhitespace) +112
System.Xml.XmlDocument.Load(XmlReader reader) +108
System.Web.UI.WebControls.XmlDataSource.PopulateXmlDocument(XmlDocument document, CacheDependency& dataCacheDependency, CacheDependency& transformCacheDependency) +557
System.Web.UI.WebControls.XmlDataSource.GetXmlDocument() +153
System.Web.UI.WebControls.XmlDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +27
System.Web.UI.WebControls.Repeater.GetData() +35
System.Web.UI.WebControls.Repeater.CreateControlHierarchy(Boolean useDataSource) +220
System.Web.UI.WebControls.Repeater.OnDataBinding(EventArgs e) +51
System.Web.UI.WebControls.Repeater.DataBind() +75
System.Web.UI.WebControls.Repeater.EnsureDataBound() +55
System.Web.UI.WebControls.Repeater.OnPreRender(EventArgs e) +15
System.Web.UI.Control.PreRenderRecursiveInternal() +80
System.Web.UI.Control.PreRenderRecursiveInternal() +171
System.Web.UI.Control.PreRenderRecursiveInternal() +171
System.Web.UI.Control.PreRenderRecursiveInternal() +171
System.Web.UI.Control.PreRenderRecursiveInternal() +171
System.Web.UI.Control.PreRenderRecursiveInternal() +171
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +842

Version Information: Microsoft .NET Framework Version:2.0.50727.3634; ASP.NET Version:2.0.50727.3634

We don't have an IT department, we simply host the site and don't pay maintainence on it anymore. We now face paying a lot of money to the company we bought the site off to get it fixed. Does anyone have any suggestions?

Nothing jumps out at me, but if you need a response asap, throw in a ticket.  Telerik doesn't always answer the forum posts