I am running the Windows 8.1 preview on an AMD Athlon II X2 240 processor, 2.80 GHz, with 4 GB memory. It's a Dell.

Since installing the preview, I have trouble dragging files from the desktop into a Windows Explorer window, and sometimes right-clicking on files on the desktop. I get the little throbber, and then the screen goes purple, and when the desktop returns any Windows Explorer windows have been closed. Anyone else had this same issue?

Did you install any third party extension? I suggest perform clean boot to test the issue.

1. Press Win+R to call Run box. Type msconfig and click OK to start the System Configuration utility.
2. On the General tab, click the Selective startup option, and then click to clear the Load startup items check box. 
3. On the Services tab, click to select the Hide all Microsoft services check box, and then click Disable all.
4. Click OK, and then click Restart.