if memory serves there may be an issue with GUIMiner pointing at Slush's pool. I am not sure it has been updated to the current address.
try selecting other - then enter stratum.bitcoin.cz and port 3333 to see if you can get a connection that way.
72 MH/z is about right for a low spec 5670
try selecting other - then enter stratum.bitcoin.cz and port 3333 to see if you can get a connection that way.
72 MH/z is about right for a low spec 5670
Thanks
edit: Spoke too soon
Code:
2013-07-01 20:09:19: Listener for "Default": stratum.bitcoin.cz:3333 01/07/2013 20:09:19, Verification failed, check hardware! (1:0:Redwood, 8e454765)