lost connection to db

All of a sudden I am unable to connect to a db. I am told to by object explorer that:

A network related or instance specific error occured while establishing connection to sql server. The server was not found or was not accessible.  Verify the name is correct...(provider: Named Pipes Provider, error: 40- Could not open a connection to the server)(Microsoft Sql Server, Error: 2).

After reading for a while regarding solutions for this kind of problem, the only thing I could do was rebuild. So I followed the instructions and entered the following line (cmd) to rebuild--tried restarting service but that did not work.

setup /QUIET /ACTION=REBUILDDATABASE /INSTANCENAME=ACCUCHEK360 /SQLSYSADMINACCOU
NTS="name of computer"\"name" /SAPWD=STRONGPASSWORD    ("" is mine).

I received an error Exception has been thrown by the target of an invocation.

LookeException summary:
The following is an exception stack listing the exceptions in outermost to innermost order
Inner exceptions are being indented

Exception type: System.Reflection.TargetInvocationException
    Message:
        Exception has been thrown by the target of an invocation.
    Data:
      DisableWatson = true
    Stack:
        at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
        at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
        at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
        at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
        at Microsoft.SqlServer.Configuration.SetupExtension.ObjectDatastoreIntegration.SetInputSettingInputPropertiesOnObject(Object pendingObject, TextWriter loggingStream)
        at Microsoft.SqlServer.Configuration.SetupExtension.ActionDatastoreIntegration.SetPropertiesOnRunningAction(ActionKey key, TextWriter loggingStream)
        at Microsoft.SqlServer.Setup.Chainer.Workflow.ActionMetadata.NotifyInExecution(ActionKey actionRunning, TextWriter loggingStream)
        at Microsoft.SqlServer.Setup.Chainer.Workflow.ActionInvocation.InvokeAction(WorkflowObject metabase, TextWriter statusStream)
        at Microsoft.SqlServer.Setup.Chainer.Workflow.PendingActions.InvokeActions(WorkflowObject metaDb, TextWriter loggingStream)
        at Microsoft.SqlServer.Setup.Chainer.Workflow.ActionEngine.RunActionQueue()
        at Microsoft.SqlServer.Setup.Chainer.Workflow.Workflow.RunWorkflow(WorkflowObject workflowObject, HandleInternalException exceptionHandler)
        at Microsoft.SqlServer.Configuration.BootstrapExtension.ExecuteWorkflowAction.ExecuteAction(String actionId)
        at Microsoft.SqlServer.Chainer.Infrastructure.Action.Execute(String actionId, TextWriter errorStream)
        at Microsoft.SqlServer.Setup.Chainer.Workflow.ActionInvocation.ExecuteActionHelper(TextWriter statusStream, ISequencedAction actionToRun)
    Inner exception type: System.ArgumentNullException
        Message:
                Value cannot be null.
                Parameter name: InstallMediaPath
        Stack:
                at Microsoft.SqlServer.Configuration.MsiExtension.InitializeMsiExtension.set_InstallMediaPath(String value)
d in the summary.txt and this is the error msg there:

All I want is to get a copy of my db so I can make back up and store it. What should I do?

Please help.

t