Had any serious crashes lately? If so run scandisk before you do anything.
Afterwards if you want to be ultra cautious you may want to run under the command prompt (cmd): sfc /scannow and then run Windows update.
If you have a third party firewall make sure X2 is configured the same as X1 (if you didn't do anything here ignore this).
Then go through all the settings in preferences in X1, and compare them to the preferences in X2.
You might want to compare your AUD.INI files as well, but remember they may be slightly different for a reason.
Then see if you can get sound out of a brand new project.
ps don't run X1 and X2 at the same time, oh and update your drivers! (Yes X1 maybe working but it could make all the difference).