Windows Service needs to restart to keep its functioning

I have created a windows service that sends email reminders every 30 seconds. 10 days before it was working fine but now it doesn't run until it is restarted manually from services.msc

Once it is restarted, the service then sends email.

The window service is written in C# and in Visual Studio 2005.

Let me know if any info needed.

Thanks for your inputs!

UPDATED:Event viewer error descripition

Timestamp: 4/5/2011 6:03:53 AM

Message: There is no explicit mapping for the categories 'Application'.

The log entry was:

Timestamp: 4/5/2011 6:03:53 AM

Message: Error Type: ERR_RETRIEVING_DATA

Entity Information: Get

Session Info: Object reference not set to an instance of an object.

Category: Application

Priority: -1

EventId: 0

Severity: Information

Title:

Machine: VPS

App Domain: EinsteinEMRServerSetupSupport.exe

ProcessId: 3660

Process Name: C:\SOAPe Platinum Plus\EinsteinEMRServerSetupSupport.exe

Thread Name:

Win32 ThreadId:3680

Extended Properties:

Category:

Priority: -1

EventId: 6352

Severity: Error

Title:

Machine: VPS

Application Domain: EinsteinEMRServerSetupSupport.exe

Process Id: 3660

Process Name: C:\SOAPe Platinum Plus\E开发者_JAVA百科insteinEMRServerSetupSupport.exe

Win32 Thread Id: 3680

Thread Name:

Extended Properties:

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Many times for windows services' problems, looking at windows event's logs enables to target disfunction, but as said by Jon Skeet : Hard to give you more precise orientation without details.

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Ok, ERR_RETRIEVING_DATA seems a bit tricky. Sounds like a I/O problems on hard drive (due to termination), but strange to see it works after a restart. It could be anything in the system.

What is the information you're trying to get ?
How do you try to get it ?

Does your problem appears after a reboot of the machine ?
Wouldn't it be because of your service's list start order ?

If "Your" service start before the resources that it needs, you would be unable to reach it (For example, starting before MSMQ while trying to push/get messages).