default large folder icons in windows vista

Configure the view how you want it, go to Tools -> Folder Options -> View tab -> click on Apply to Folders. You will need to repeat this for each folder type in Vista (under the Customize tab in the folder properties). Note that you can change the folder type on a folder, apply the view settings, change it to the next type, apply the view settings, etc.
 
 If you find that "Apply to Folders" is grayed out then you'll need to turn off UAC before you configure the view settings. To turn off UAC, open Control Panel -> User Accounts ->  Turn User Account Control on or off -> uncheck the box, click OK, restart the computer.
 

Hello Mr username. Apart from your first part of the solution: what has UAC to do with folder options? I never saw any UAC restrictions here and for sure this is no reason to disable it.

You shouldn't be able to access "folder options" having UAC activated. you are administrator on a machine with UAC off, so that's why you can access it.

"you are administrator on a machine with UAC off, so that's why you can access it." - suuuure. Folder options are something everyone can configure, no elevation needed. Do you see any shield icon, Tomeryos? And even if, this is no reason to disable UAC.

Re UAC, yes, you shouldn't need turn off UAC but I have found that the Apply to Folders setting was sometimes grayed out and to get it back I had to turn off UAC and then back on.

My UAC is off and my apply to all folders button is still grayed out.

Also i don't see any options in folder options which makes the icons bigger.