I have a Windows 7 PC. When I right click on an icon, it takes 10 seconds for the menu bar to show.
Here is what eventually appears:

Why does it take so long? Or any ideas on a systematic way to troubleshoot?
I have a Windows 7 PC. When I right click on an icon, it takes 10 seconds for the menu bar to show.
Here is what eventually appears:

Why does it take so long? Or any ideas on a systematic way to troubleshoot?
You will certainly get better experience when you keep on a clean context menu, what you need to troubleshoot is autoruns from Microsoft.

usage is simple : Browse to the Explorer Tab and uncheck every extra extension you are not using (I doubt if you are using any from there :) and especially the Abobe stuffs.
you can get them back later if you need some.
It could be that Dropbox is requesting something from the internet every time you right-click and doesn't respond (to display the context menu) until a response is received.
Try disconnecting your pc from the network (or disable/close Dropbox) and see if there is any difference in the behavior.