如何强制执行一个运行的t-sql查询(完成一半)?

I have database on Sql Server 2008 R2. On that database a delete query on 400 Million records, has been running for 4 days , but I need to reboot the machine. How can I force it to commit whatever is deleted so far? I want to reject that data which is deleted by running query so far. But problem is that query is still running and will not complete before the server reboot.I have database on Sql Server 2008 R2. On that