I've done some research on this error with varied results, few of which seem to fit my causes or symptoms.
I work in a tech support office, and somebody brought their Windows Vista laptop in to us. It is running Windows Vista Home Basic, and Control Panel would not open. This is a legitimate version of Windows, and before everything went wrong, MGA Diag verified it as genuine. After trying a few solutions we found online, with no progress, my work colleague switched the startup type of the Software Licencing (slsvc) process. This resulted in the machine no longer being able to boot into non-Safe Mode Vista. It gets as far as logging in to the default user, when it springs up the error "A problem occurred when Windows tried to activate. Error Code 0x80070426.". After the error is closed, it logs the user back out. Further attempts to log in again result in the same error. Even when the Software Licensing process is switched back to automatic startup, with user Network Service, the error continues.
Here is the MGA Diag report, run from Safe Mode, as the laptop is now.
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Diagnostic Report (1.7.0095.0):
-----------------------------------------
WGA Data-->
Validation Status: Invalid License
Validation Code: 50
Online Validation Code: 0x80070426
Cached Validation Code: N/A, hr = 0x80070426
Windows Product Key: *****-*****-GD2PK-BD3R2-44MV3
Windows Product Key Hash: f7FPE6g/CLFmnJ4E6GbEU9Xn1sA=
Windows Product ID: 89572-OEM-7332166-00021
Windows Product ID Type: 2
Windows License Type: OEM SLP
Windows OS version: 6.0.6001.2.00010300.1.0.002
CSVLK Server: N/A
CSVLK PID: N/A
ID: {CCC827D8-BC0D-4659-8BB1-80D6A147148E}(1)
Is Admin: Yes
TestCab: 0x0
WGA Version: N/A, hr = 0x80070002
Signed By: N/A, hr = 0x80070002
Product Name: Windows Vista (TM) Home Basic
Architecture: 0x00000000
Build lab: 6001.vistasp1_gdr.080425-1930
TTS Error:
Validation Diagnostic:
Resolution Status: N/A
WgaER Data-->
ThreatID(s): N/A, hr = 0x80070002
Version: 6.0.6002.16398
WGA Notifications Data-->
Cached Result: N/A, hr = 0x80070002
File Exists: No
Version: N/A, hr = 0x80070002
WgaTray.exe Signed By: N/A, hr = 0x80070002
WgaLogon.dll Signed By: N/A, hr = 0x80070002
OGA Notifications Data-->
Cached Result: N/A, hr = 0x80070002
Version: N/A, hr = 0x80070002
WGATray.exe Signed By: N/A, hr = 0x80070002
OGAAddin.dll Signed By: N/A, hr = 0x80070002
OGA Data-->
Office Status: 100 Genuine
Microsoft Office Excel 2007 - 100 Genuine
Microsoft Office PowerPoint 2007 - 100 Genuine
Microsoft Office Publisher 2007 - 100 Genuine
Microsoft Office Word 2007 - 100 Genuine
OGA Version: N/A, 0x80070002
Signed By: N/A, hr = 0x80070002
Office Diagnostics:
025D1FF3-282-80041010_025D1FF3-170-80041010_025D1FF3-171-1_025D1FF3-434-80040154_025D1FF3-178-80040154_025D1FF3-179-2_025D1FF3-185-80070002_025D1FF3-199-3_E2AD56EA-338-8009_E2AD56EA-339-2ee7_16E0B333-89-80004005_B4D0AA8B-1029-80004005_E2AD56EA-338-8009_E2AD56EA-339-2ee7_16E0B333-89-80004005_B4D0AA8B-1029-80004005_E2AD56EA-338-8009_E2AD56EA-339-2ee7_16E0B333-89-80004005_B4D0AA8B-10
Browser Data-->
Proxy settings: N/A
User Agent: Mozilla/4.0 (compatible; MSIE 7.0; Win32)
Default Browser: C:\Program Files\Internet Explorer\iexplore.exe
Download signed ActiveX controls: Prompt
Download unsigned ActiveX controls: Disabled
Run ActiveX controls and plug-ins: Allowed
Initialize and script ActiveX controls not marked as safe: Disabled
Allow scripting of Internet Explorer Webbrowser control: Disabled
Active scripting: Allowed
Script ActiveX controls marked as safe for scripting: Allowed
File Scan Data-->
Other data-->
Office Details:
<GenuineResults><MachineData><UGUID>{49B2D324-41F9-4FEF-AF28-859A79DE5335}</UGUID><Version>1.7.0095.0</Version><OS>6.0.6001.2.00010300.1.0.002</OS><Architecture>x32</Architecture><PKey>*****-*****-*****-*****-44MV3</PKey><PID>89572-OEM-7332166-00021</PID><PIDType>2</PIDType><SID>S-1-5-21-398890772-1336224415-2877287701</SID><SYSTEM><Manufacturer>Hewlett-Packard</Manufacturer><Model>Presario
V3000
(RZ826PA#ABG)</Model></SYSTEM><BIOS><Manufacturer>Hewlett-Packard</Manufacturer><Version>F.39</Version><SMBIOSVersion
major="2"
minor="4"/><Date>20071122000000.000000+000</Date></BIOS><HWID>57023007018400EE</HWID><UserLCID>0C09</UserLCID><SystemLCID>0409</SystemLCID><TimeZone>Tasmania
Standard Time(GMT+10:00)<
/TimeZone><iJoin>0</iJoin><SBID><stat>3</stat><msppid></msppid><name></name><model></model></SBID><OEM><OEMID>HPQOEM</OEMID><OEMTableID>SLIC-MPC</OEMTableID></OEM><BRT/></MachineData><Software><Office><Result>100</Result><Products><Product
GUID="{90120000-0016-0000-0000-0000000FF1CE}"><LegitResult>100</LegitResult><Name>Microsoft
Office Excel
2007</Name><Ver>12</Ver><Val>AB884BFF5CD3D86</Val><Hash>w7U/0hPt7khlCg85y4OdiMkDB/I=</Hash><Pid>89385-707-5609323-63965</Pid><PidType>14</PidType></Product><Product
GUID="{90120000-0018-0000-0000-0000000FF1CE}"><LegitResult>100</LegitResult><Name>Microsoft
Office PowerPoint
2007</Name><Ver>12</Ver><Val>63BE2BA84B58D86</Val><Hash>mKQhNexLDIMFc3HTH8q2M/8Yps0=</Hash><Pid>89400-707-9021351-63448</Pid><PidType>14</PidType></Product><Product
GUID="{90120000-0019-0000-0000-0000000FF1CE}"><LegitResult>100</LegitResult><Name>Microsoft
Office Publisher
2007</Name><Ver>12</Ver><Val>AEFB93ABBD88D86</Val><Hash>snpKj39yYqTxaEOuqIhA2PAzVOA=</Hash><Pid>89404-707-6292324-63009</Pid><PidType>14</PidType></Product><Product
GUID="{90120000-001B-0000-0000-0000000FF1CE}"><LegitResult>100</LegitResult><Name>Microsoft
Office Word
2007</Name><Ver>12</Ver><Val>AB884BFF5CD3D86</Val><Hash>w7U/0hPt7khlCg85y4OdiMkDB/I=</Hash><Pid>89407-707-5609323-63886</Pid><PidType>14</PidType></Product></Products><Applications><App
Id="16" Version="12" Result="100"/><App Id="18" Version="12"
Result="100"/><App Id="19" Version="12" Result="100"/><App
Id="1B" Version="12"
Result="100"/></Applications></Office></Software></GenuineResults>
Spsys.log Content: 0x80070002
