Question: I have a checkbox column in gridview and getting its Click event. But I just has relised I do not need Click event rather I need to know the events if checkbox is checked or unchecked on Client side. But these events are not available.

Please guide how to handle this.

Answer: 
*By suggestion of Marc Gravell, I change my comment into an answer:*

I can think of two reasons why your code breaks in VB.NET:

* If in VB you use somewhere in your code On Error Resume Next (oh horror), then you don't see it in VB, but will see it in VB.NET (because it doesn't allow errors to be ignored).
* You tagged Excel. I assume you went from an older version of Excel to a newer version or you moved your code from Excel to stand-alone VB.NET. A whole host of non VB-related changes might cause an error to popup.

Why you get an error about a printer not being available (or any of the other pointers Jon gave you), I don't know, but you might try that specific question on <http://superuser.com>.
Interop sucks basically. Check your processes (task manager) ... there should be at least one excel.exe process that isn't visible on the desktop. Kill them since they might have the file in use. That causes your 'Can not open the source file C:\file.xlsx' error. And who knows it might also fix your other error.

If it doesn't, check if you installed the latest interop assemblies and use those. It helps when you're dealing with Office products.
<http://msdn.microsoft.com/en-us/library/15s06t57(v=VS.100).aspx>