List Item event receiver not working: SharePoint 2010

Question

Hi,
I have ceated one custom list and also created a Event reciever solution using Visual Studio 2010.
In the event reciever I added ItemAdded, ItemUpdated events and did some my business related coding.
It was worked very well when I add/edit the list item.
But, now suddenly it stopped working!, I i really don't know what went wrong suddenly.
Only thing I did is, created one more solution event reciver and added some more columns to the list.
I then reverted all these changes and deleted the new event reciever from the site solution.
I am able to build and deploy the solution in VS 2010, and I could see the solution in site solution but events are not firing when I created/edited the list items
Any idea what went wrong and how can I get it back to work.
It has spoiled my all the work and I am unable to proceed.
Please let me know if anyone have any inputs.
I also tried following things: restart visual studio and deploy again, restart IIS, restart system itself, actvate-deactivate solution manually in site, GAC the dll manually.
But nothing has worked for me.
One more thing, I am using this solution as Sandbox solution and when I tried to make Sandbox as false and then deploy it gave me error like:
"Error occurred in deployment step 'Activate Features': Operation is not valid due to the current state of the object."
Is this something related to my above problem?
Thanks, Sharath

Answer 1

Check Event receivers using powershell:-
Add-PsSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
$spWeb = Get-SPWeb -Identity "sitename"
$spList = $spWeb.Lists["yourlistname"]
$spList.EventReceivers | Select assembly,name
Replace "sitename" with your site url and "yourlistname" with list name.
Once you confirm  the event receivers, use below to delete them
Add-PsSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
$spWeb = Get-SPWeb -Identity "your site url"
$spList = $spWeb.Lists["TrackTravel"]
$evts = $spList.EventReceivers | where {$_.Assembly -eq ""your assembly"}
$evts
if ($evts.Count -gt 0) {
            foreach ($evt in $evts) {
                Write-Host("Deleting..." + $spList.RootFolder.ServerRelativeUrl + ", " + $evt.Type)
                $evt.Delete()
Once you run this, you can now redeploy your solution.
http://social.technet.microsoft.com/Forums/en/sharepoint2010general/thread/a911a64f-b4cb-49a8-ad61-899d4e418c2a
ganesh