The other day I logged onto our server to see SQL was using 100% cpu and the server was slowed to a crawl. I decided to stop SQL and restart it. However, it refused to stop properly and stopped responding. After playing around with it eventually I got it restarted and running again.
However, all queries against it are now going 10-30 times slower, and in some cases affect the performance of the server.
I've been googling for solutions but I can't see anything addressing a global issue with SQL running slow. The CPU usage isn't abnormal and there is plenty of free ram - in fact, SQL is using only about 300mb whereas previously it used to be around 20gb, which may be part of the issue.
I created a brand new database and when I attempt to populate it, it goes about 30 times slower than it used to, and the server becomes very unresponsive.
Could it be something simple that needs resetting or a repair that needs doing after it broke before?