I cannot open internet sites in safari, I do have internet connection
See above
iMac
See above
iMac
Power off the router. Wait awhile. Power it back on. Wait until all the lights are lit up properly.
It will take a while.
Restart the computer.
Start up in Safe Mode
Dominic, thanks for the above, but this did not solve the problem. It appears that I get the wireless connection then the Mac turns it off. Is there a program that may of been loaded that would do this?.
Is there a system diagnosis that I can run to check this?
I cannot open internet sites in safari, I do have internet connection