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: 
Supposedly, this error is to do with [no printer being available](http://bytes.com/topic/visual-basic-net/answers/513253-excel-interop-no-printers-installed-error). I don't know why you'd get it in VB.NET but not in VB... but you might want to look at your printer permissions etc.

EDIT: [This post](http://www.hagrin.com/319/exception-hresult-0x800a03ec-excel-net-sql-and-windows-server-2008) may be useful as well, showing DCOM service changes with regards to identity.

EDIT: Ooh, looks like the error can mean multiple things. [This MSDN page](http://msdn.microsoft.com/en-us/library/6s0wczt9%28v=vs.80%29.aspx) mentions it in a regional settings context...
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>