Start difficulties after winter

Hey guys. I’ve got a big problem! The first April is coming up and I don’t want to be a minute longer without my bike (this has a season mark) than I have to. I took on the task of mopping her out a week ago and getting her out of her hibernation. She was standing dry under a shelter (since December). Now I’ve tried to start her and there’s my problem. She doesn’t start! First I read what I’m doing. I have charged the battery, even if the starter spins as it should! It wasn’t and so I called at the motorcycle shop near me (they have at the moment 3 weeks advance, otherwise I wouldn’t have the problem now!). They said that if it smells like gasoline at the start, the carburetor is free (which in itself is a good thing, because it does!). The spark plugs are probably the problem then, it said! So I bought 4 new ones and changed them off (also tested if they spark; d as do they!). Now it still doesn’t start – I’m stunned! Fuel is in the tank (fresher), the battery is fully charged, the spark plugs are new, obviously it makes the gasoline in the engine – but it drove without I pushed it this year not yet a meter! I would love help endlessly, tips or ideas about what it could be (not such as “emergency switch on” or “stands not folded”, that I checked!). All those who help me!