I only have one account as I'm the only one using it. Does this mean I won't get the password dialog up when installing apps using right-click admin?

ThIs
I only have one account as I'm the only one using it. Does this mean I won't get the password dialog up when installing apps using right-click admin?

You should only get yes/no dialog to confirm - a security thingy since applications normally run as user which cannot write everywhere on disk or registry.
 
You could try and drag-n-drop a file into c:\program files - you should get a dialog to confirm that operation since admin rights are needed.
 
If this does not happend - maybe your UAC is disabled, turned off - and this may interfere with installers.
But that is a manual operation and something you would be aware of.
 
Go to Start -> Run and type msinfo32 och execute.
There you get version and if SP1 is really installed.

Tried dragging a file into c:\program files and the dialog came up. So my UAC is turned on.

Found the problem. When I used Windows update for updating, the update wasn't done even though it said it was. Got the message that SP1 now is installed. Strange, when that wasn't the case. I downloaded SP1 and installed it manually and voila...The 64-bit installation = Success.
 
A big thanks to all you guys giving me tips and advices in this issue. Couldn't have made it without you :)

Hello This and welcome to the forums. 
I am glad that you got Artist installed at last.  And so...could you please correct the thread name with "solved" or some indicator that your problem is past?   Thanks.