My string will not go into the hole and I removed the 4 screws. I can not get it apart. How do I remove this head part to see why the string will not push into the hole?

On the Hofner Shorty, you will need to manually remove the bridge with a screw drive or similar tool. There are large screws on either side of the bride that when removed, the bridge will come off entirely. At this point, you can unwind the strings from the tuners on the head of the guitar, which will completely slacken the strings. Push the strings out the back side of the bridge to remove the old string, and insert the new strings via the same hole in the corresponding order they were removed. Make sure all new strings are looped through the bridge, then set the bridge in place. At this time, with all the strings hooked in and the bridge set in place, you can now attach the strings to the tuners.

Once you remove the spool cap and the spool, you cannot remove the head from the motor. It is not a replacement part.
Ryobi P2002 Cordless String Trimmer Parts

Its a 'clockwise' thread to undo it. It may also require a pin to lock the head from turning

A typical trimmer has a small bump knob, an inner spool with the plastic string wound on it and the housing for that which is the string head.To remove the small bump knob, hold string head firmly and turn the bump knob counterclockwise. To remove the head entirely, first remove the bump knob. Next, remove the inner spool with string. What should be left is the spring with the end of the gear shaft showing. Some heads are locked on and some just slip over the end of the shaft. Check the gear drive just above the string head for any holes in the collar. An object can be placed in one of the holes to lock the drive and twist the head off.Ryobi's use retaining clips on the shaft which have to be removed.

Oh NO! Loved that toy when I was a kid. With a bright light source, check the sides and the back of the toy for the screws. They are there somewhere. Sometimes they have little caps over them that you'll need to remove first.
You may be able to hold the toy upside down and extract the string back out of the hole with a pair of tweezers. I know it's a long shot.
Good luck!

Remove orange sheild,remove single screw holding head in shaft then grab head with pliers and twist side to side until complete head is free.You should then be able to grab part of shaft.On power head loosen screws {about one turn each} that hold two white case halves near trigger,I think there are four,then there is a single torx screw on the bottom of lower case half in the middle that must be taken out to allow tube to be removed.Romove flexshaft from top.Check 4 plastic burnt to flexshaft,if there is you must replace tube liner as well,usally around bent part of tube the liner will go bad.

Pardon the long winded answer. I have had a similar same issue on this trimmer TWICE in the first 3 months. What I found on my trimmer is that there is a spring buffer/assist built into the starter assy between the rope pulley and the plastic part that engages the cogs on the motor. The plastic part that engages the motor has a hole in it to retain one end of the spring and the other end of the spring fits in a slot in the rope pulley. The plastic part with the hole appears to be poorly designed and allows the spring assist spring to fall out of the hole and jam the entire assembly preventing the rope from returning. Pulling it apart allows the recoil spring to escape from under it's cover and prevents it from engaging. Yes, removing the spring can be a little exciting -- take your time and cover the housing opening with a towel before removng the spring to keep it from flying across the room. I rewound the spring by driving a nail into my workbench and using it to retain the center hole and wound the spring until it would fit inside the metal spring cover. There's a bump in the outer winding that fits in a hole in the spring cover and then it slides over a peg in the plastic housing. The cover will retain the spring as you put it back into the housing as long as you take your time. The circled inner end of the spring should show in the center hole and it engages the other part of the recoil assembly that engages the cogs on the motor. Check to see if the assist spring is engaged on both ends before tightening the 3 retainers. All-in-all a pretty poor design that has me looking for another trimmer and this one's going in the trash.

Go to home depot. look at the floor model and the replacement spools they sell there. Reverse engineer the stringing process or but a pre-loaded spool.
Otherwise,
1. Squeeze the tabs on the side of the head of the unit to remove the spool cover.
2. remove spool.
3. place end of string in small hole in center ring of spool.
4. wide spool with string in the direction of the arrows printed on the spool. DO NOT OVERLOAD!.
5. snap string into notch on spool and cut string leaving 6" exposed.
6. thread 6" of string through hole in side of unit head, replace spool, and replace cover.
7. go cut grass.

take a light and look into the clutch hole
you will either need a torx or star type nut driver or a allen or hex head nut driver to fit in the hole and turn the screw ccw while holding the flywheel.
Make note where all comes off and all goes back in reverse when fixed.also after you remove the clutch housing you will be stareing at the clutch shoes next and it will have markings on which way to turn it for removal.

This is for the Black and Decker GH1000 string trimmer. There are 20 screws to remove altogether. The last screw is under the black label with instructions on using the button to extend the shaft. The screw hole is just above the white line on the label-you have to poke a hole in the label! Very tricky!