Windows Update failed

Hi, we are running a small Domain with few Windows XP Clients connected. All systems are working fine except one client. It is not able to install any of the updates. There is no problem in downloading the updates but installation gets failed every time. We tried out several things to fix it out but its been more than a day now facing the problem and yet nothing worked. Hence I came here seeking for some help.

For more help I am attaching the WindowsUpdate.log file. Please help.

Agent * Updates to install = 1
Agent * Title = Definition Update for Windows Defender - KB915597 (Definition 1.21.2837.1)
Agent * UpdateId = {97F3FCB3-AD67-4CC7-9E76-971EC23170CE}.100
Agent * Bundles 1 updates:
Agent * {70BA02A8-BE7D-46CC-A80B-1F84B8529DB1}.100
REPORT EVENT: {A313645A-76DC-43DC-A4B6-6B7A191A39EF} 2007-08-17 10:27:40:421-0400 1 147 101
{00000000-0000-0000-0000-000000000000} 0 0
Windows Defender Success Software Synchronization
Windows Update Client successfully detected 1 updates.

Misc =========== Logging initialized (build: 7.0.6000.374, tz: -0400) ===========

Misc = Process: C:\WINDOWS\system32\wuauclt.exe
FATAL: Error: 0x80004002. wuauclt handler: failed to spawn COM server
Handler FATAL: 0x80004002: ERROR: Remote update handler container process created (PID: 3608), but exited before signaling event

COMAPI >>-- RESUMED -- COMAPI: Install [ClientId = Windows Defender]
Agent * WARNING: Exit code = 0x80004002
Agent *********
Agent ** END ** Agent: Installing updates [CallerId = Windows Defender]
Agent *************
Agent WARNING: WU client failed installing updates with error 0x80004002
COMAPI - Install call failed
COMAPI - Reboot required = No
COMAPI - WARNING: Exit code = 0x80240FFF; Call error code = 0x80004002
COMAPI ---------
COMAPI WARNING: Operation failed due to earlier error, hr=80004002
COMAPI FATAL: Unable to complete asynchronous installation. (hr=80004002)
COMAPI -- END -- COMAPI: Install [ClientId = Windows Defender]

Thank you.

Well there could be several reasons for failing updates installation but before going into hardcore troubleshooting i will suggest you to fist check if your Time is set correct on your Computer and matches the domain time.

If it is correct then launch RUN command and try to Re-register the following DLLs for the update Engine:
net stop wuauserv click [OK]
regsvr32 wuapi.dll click [OK]
regsvr32 wuweb.dll click [OK]
regsvr32 atl.dll click [OK]
regsvr32 wups2.dll click [OK]
regsvr32 wuaueng1.dll click [OK]
regsvr32 wups.dll click [OK]
regsvr32 MSXML3.dll click [OK]
regsvr32 wucltui.dll click [OK]
regsvr32 wuaueng.dll click [OK]
net start wuauserv click [OK]

Now turn off all Firewalls and Defender, reboot you system and then start running the updates again. See if it gets installed now.

Thank you very much for the help Janos. I followed all the steps you mentioned above and now it seems to be working fine. So far it has hinished installing more than 80% of the updates.