GUI Miner no responses to getwork, and Verification failed

Question

I just starting with mining today I have everything set up for slush pool on GUIMiner - v2012-12-03 . I'm not sure what is wrong but this is what the console says

2013-06-21 01:37:26: Listener for "GPU Miner" started
2013-06-21 01:37:28: Listener for "GPU Miner": stratum.bitcoin.cz:3333 21/06/2013 01:37:28, checking for stratum...
2013-06-21 01:37:28: Listener for "GPU Miner": stratum.bitcoin.cz:3333 21/06/2013 01:37:28, started OpenCL miner on platform 0, device 0 (Juniper)
2013-06-21 01:37:28: Listener for "GPU Miner": stratum.bitcoin.cz:3333 21/06/2013 01:37:28, no response to getwork, using as stratum
2013-06-21 01:37:39: Listener for "GPU Miner": stratum.bitcoin.cz:3333 21/06/2013 01:37:39, Verification failed, check hardware! (0:0:Juniper, a4627d39)
2013-06-21 01:37:51: Listener for "GPU Miner": stratum.bitcoin.cz:3333 21/06/2013 01:37:51, Verification failed, check hardware! (0:0:Juniper, 9fcd8ac2)
2013-06-21 01:37:52: Listener for "GPU Miner": stratum.bitcoin.cz:3333 21/06/2013 01:37:52, Verification failed, check hardware! (0:0:Juniper, 87fcf304)
2013-06-21 01:37:55: Listener for "GPU Miner": stratum.bitcoin.cz:3333 21/06/2013 01:37:55, Verification failed, check hardware! (0:0:Juniper, 5aa4b0f1)!

I also took a screenshot of the settings I have chosen here.

Answer 1

An answer can be found on bitcoin talk

https://bitcointalk.org/index.php?topic=177855.msg1852355#msg1852355

Quote from deepceleron on bitcoin talk

This is your GPU returning invalid hashes from it's kernel. This is because new drivers are crap for older cards.

• Uninstall AMD APP SDK

• Uninstall AMD Catalyst Install manager: choose "uninstall all software", make sure you have only a VGA driver after restart.

• Manually remove these files not removed by the installer; any other obvious ATI files with the same file date:
  C:\Windows\System32\amdocl64.dll C:\Windows\System32\amdoclcl64.dll C:\Windows\System32\OpenCL.dll C:\Windows\SysWOW64\amdocl.dll
  C:\Windows\SysWOW64\amdoclcl.dll C:\Windows\SysWOW64\OpenCL.dll

• Install just the Catalyst 11.11 driver package (no SDK is needed; the AMD APP runtime is included with driver)

• Mine just a bit slower on your 6870 than a 5830 would.

Better: - use cgminer - set phatk worksize to 256 and underclock GPU RAM to 300MHz for best power efficiency and higher hashrate

The big thing to take away from this: set phatk worksize to 256 and underclock GPU RAM to 300MHz for best power efficiency and higher hashrate

A suggestion i can give you is that bitcointalk can be a great place to find the answer to a lot of off the wall questions related to bitcoin or any alt-coin.