Vaadin Stopped Working Abruptly

Hi,
We were using vaadin 7.6.8 in a project. Today it stopped working. 
We tried older versions of project which work perfect but nothing changed.

After this error, tried to upgrade Vaadin to 7.7.3. But it doesn't work, too. What may be the problem?

It is compiled but when we want to deploy we get below message.

java.lang.NoSuchMethodError: com.vaadin.ui.UI.addDetachListener(Lcom/vaadin/server/ClientConnector$DetachListener;)Lcom/vaadin/shared/Registration;
    at com.vaadin.spring.internal.UIScopeImpl$UIBeanStore.create(UIScopeImpl.java:281)
    at com.vaadin.spring.internal.BeanStore.get(BeanStore.java:62)
    at com.vaadin.spring.internal.SessionLockingBeanStore.get(SessionLockingBeanStore.java:46)
    at com.vaadin.spring.internal.UIScopeImpl.get(UIScopeImpl.java:81)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:337)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:217)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:350)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:331)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:968)
    at com.vaadin.spring.server.SpringUIProvider.createInstance(SpringUIProvider.java:184)
    at com.vaadin.server.communication.UIInitHandler.getBrowserDetailsUI(UIInitHandler.java:191)
    at com.vaadin.server.communication.UIInitHandler.synchronizedHandleRequest(UIInitHandler.java:74)
    at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1422)
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:379)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:769)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1667)
    at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:172)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1650)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:583)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
    at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1125)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1059)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:110)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
    at org.eclipse.jetty.server.Server.handle(Server.java:497)
    at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311)
    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:248)
    at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:610)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:539)
    at java.lang.Thread.run(Thread.java:745)

It is solved, problem was about latest vaadin-spring (version 2.0)
vaadin-spring-1.0.0 is working.