i reinstalled windows 8 on my laptop an hp 255. the product key provided with the disc worked for installation. when l try activating windows it is giving me error code 0x8007007b, filename directory name or volume label syntax is incorrect. i also try updating my product key using command prompt and it gave me a success massage but when i try to activate it gave the same error massage, and when i check the key it give me a different key. what can i do to activate windows?

You might want to look at this: http://support.microsoft.com/kb/929826/en-us

Can you paste the output of the following command:

slmgr /dlv

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Windows Script Host
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Software licensing service version: 6.2.9200.16384



Name: Windows(R), Professional edition

Description: Windows(R) Operating System, VOLUME_KMSCLIENT channel

Activation ID: a98bcd6d-5343-4603-8afe-5908e4611112

Application ID: 55c92734-d682-4d71-983e-d6ec3f16059f

Extended PID: 05426-01787-000-000011-03-1033-9200.0000-0502014

Installation ID: 561825464778250808086348083503879552716304621950650852455357921

Partial Product Key: J8CK4

License Status: Notification

Notification Reason: 0xC004F056.

Remaining Windows rearm count: 1000

Trusted time: 2/19/2014 11:51:04 PM

Configured Activation Type: All

Please use slmgr.vbs /ato to activate and update KMS client information in order to update values.




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OK   
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Your computer needs to be on the same network as your company's KMS Server in order to activate.

As you can see based on this: Description: Windows(R) Operating System, VOLUME_KMSCLIENT channel

The machine is a client to a KMS server. So if this is your work PC or you used a media provided by your organization you would need to connect it your corporate network in order for it to be activated.

Where did you get the media to install the OS? Did it come with your laptop?