I know I've been gone a long time but I've run into a prob that needs PSC expertise.
I have a screenshot of an internal website at 1920x1080 that the biz owner wants to print on a 2'x3' signage at 300DPI.
What's the best method to get the image to this size without it looking like blurry crap?
Short answer: You can't
Resolution cannot be added to an image. It will always look crappy when scaled up that much. Sorry.
Depending on the image, you may be able to run some filters that can emulate a cleaner result...