This machine could also, potentially, be like the Toshiba C55T-5300 I just tried to replace the keyboard in. The keyboard may be "fused" to the case with a metal support plate that has plastic support pins "mushroom melted" to hold that plate into place.
One thing I can assure you is that you will need to remove all the screws from the underside of the computer then, after having done so, gently pry up on the keyboard surface cover of the laptop from one of the corners (I prefer getting under right next to the hinge, but not using the hinge itself as the fulcrum for your pry lever) and working your way around.
Some island style keyboards are held on to the cover by screws. Others, like in the above mentioned Toshiba, are not. I can't find a Maintenance and Service Guide specific to the model you're working with at the HP support site. That's a pity, as they're often available and give excellent step-by-step instructions, including illustrations, for doing virtually any maintenance task you can think of.
You may not need to remove the motherboard, etc., depending on just how things are set up inside the case. I hadn't seen that John had linked directly to my tale of woe. It had a good outcome, however, in that I managed to figure out how to effect a repair on the spacebar that worked and didn't end up needing to replace the entire keyboard. Given the way yours has been compromised you're not so lucky.
If it turns out that the keyboard is not removable I would suggest that you give the whole thing a warm and thorough shower after you have it free of the machine to dissolve all of the syrup residue and allow it to dry for several days before reassembling. The syrup is very unlikely to have caused any damage beyond gumming up the works, and if you get rid of the syrup and let things dry that "gum" is gone and most likely things will work fine. People think I'm crazy when I suggest this, but when I worked in a computer lab during my college days it was routine to give the keyboards a shower after people did things like spilling a soda into them. More than 9 times out of 10 they'd work just fine again provided they were allowed to get thoroughly dry before being reconnected.
Edited by britechguy, 04 February 2018 - 01:33 PM.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
. . . the presumption of innocence, while essential in the legal realm, does not mean the elimination of common sense outside it. The willing suspension of disbelief has its limits, or should.
~ Ruth Marcus, November 10, 2017, in Washington Post article, Bannon is right: It’s no coincidence The Post broke the Moore story