first of all.. thanks every one for answering so far... I have not been playing a lot lately so atm I feel like I just started again and all the sudden I am thinking in spots I would not have thought about before.. so.. more questions to come...

Villain calling is unknwon and seemed weekend- fishy.
Villain raising the flop is a tight and pretty decent reg. 14/10 FlopAf: 2/ TurnAf:3/ RiverAf:1 Hands: 300

PokerStars No-Limit Hold'em, $1.00 BB (8 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

saw flop | saw showdown

UTG+1 ($94.50)
MP1 ($100)
MP2 ($136.50)
CO ($130.70)
Button ($58.50)
SB ($100)
BB ($139)
Hero (UTG) ($207.30)

Preflop: Hero is UTG with A, A
Hero bets $3, UTG+1 calls $3, 2 folds, CO calls $3, 3 folds

Flop: ($10.50) 5, 7, K (3 players)
Hero bets $10, UTG+1 calls $10, CO raises to $27,

fold or shove?

It seems like his range in the CO with a fish in the pot has gotta be pretty wide and there aren't really too many value hands he can have. So I would be inclined to shove. That said, I remember 100 being pretty nitty and you have the Ah so it comes down to what this reg usually does with his draws.

when villain is solid he prolly knows that UTG+1 is fishy/cally.

that said hes prolly not bluffing after you raise from UTG, bet a flop that hits your range with 2 players behind you of which one is a fish, and the fish calls your conti

also,he might just call with his draws here pretty often i think

well.. my first thoughts were something like Rosa parks including the thought on me holding the Ace of hearts... but my second was quite what you just said.. would he really bluff or semi-bluff with me barreling a flop that is hitting my UTG open raising range quite well and the calling station still to act? considering his flop AF not beeing ultra agressive....

Most of the time you are in bad shape here. Assuming the guy knows wtf is going on, he isn't going to raise his draw here because you have a strong range and there is a fish in the pot that will likely give him a whole wack of extra money when he makes his draw. Trying to force that fish out would be just awful.