COM+ Event System detected a bad return code

Hi, for the last three weeks I've had problems with the COM+ Event System service not starting up. The problem originally showed up when system restore couldn't create a restore point & media center couldn't download EPG data. I traced those problems back to dependent services of COM+ Event System which could not start.

I'm running Windows Vista Ultimate, fully patched via Windows Update.

I get the following in the Application event log when COM+ Event Service tries to start:

Log Name: Application
Source: Microsoft-Windows-EventSystem
Date: 22/01/2008 22:59:36
Event ID: 4609
Task Category: Event Service
Level: Error
Keywords: Classic
User: N/A
Computer: Morgan
Description:
The COM+ Event System detected a bad return code during its internal processing. HRESULT was 80070002 from line 196 of d:\vistartm\com\complus\src\events\tier2\service.cpp. Please contact Microsoft Product Support Services to report this error.

Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-EventSystem" Guid="{899daace-4868-4295-afcd-9eb8fb497561}" EventSourceName="EventSystem" />
<EventID Qualifiers="49152">4609</EventID>
<Version>0</Version>
<Level>2</Level>
<Task>17</Task>
<Opcode>0</Opcode>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2008-01-22T22:59:36.000Z" />
<EventRecordID>124454</EventRecordID>
<Correlation />
<Execution ProcessID="0" ThreadID="0" />
<Channel>Application</Channel>
<Computer>Morgan</Computer>
<Security />
</System>
<EventData>
<Data Name="param1">d:\vistartm\com\complus\src\events\tier2\service.cpp</Data>
<Data Name="param2">196</Data>
<Data Name="param3">80070002</Data>
</EventData>
</Event>

I can only find one mention of this particular problem online, which doesn't have a solution unfortunately. Any help you could give me would be gratefully received.