I have an old Singer 368. Why is the belt not driving drive shaft though power is getting to the machine and the manual wheel is set correctly? I cannot turn the drive wheel manually either

the hand wheel is conned to the hook shaft by a belt
if one turns without moving the other it could be a broken belt

It sounds as if the machine has not been used for quite some time. Rather than a stripped gear or gears, it sounds as if the belt connecting the hand wheel to the shaft is no longer there. This is a VERY old machine, but if you're determined to fix it, there are a number of sites as well as FB groups devoted to machine restoration that can help you. By the way -- you can download the user manual free at the Singer site -- I just took a look at it.

Hi,
There is a shaft that runs from the top of the machine to the bottom, in turn driving the bottom gear and belt. Though it is hard to see, you will probably find that the gear at the top of that shaft has the teeth broken. It is not impossible to change but definitely difficult.

Hi Donna,here's a link to your Singer,just enter your serial number to find out what year model it is. Singer Sewing Machine Company Serial Numbers

the drive belt is normally a cog type belt inside the head of the machine
I would be looking in that area and at the belt or at the tension of that belt
may be a service technician would be able to correctly adjust and fix the problem

Sounds like you might have a broken gear in the transmission. Since the Touch and Sew series (aka Touch and Swear, Sew and Throw, etc.) are so touchy about adjustments, I'd probably take this one to a good sewing machine mechanic and let him/her do the heavy lifting on this.
Parts diagrams: http://parts.singerco.com/CPpartCharts/6_6999/648E3_648E6_648E7.pdf
More: http://www.tandtrepair.com/600TandSstuff.html
(Sorry, but this is the era when Singer suddenly veered into the weeds.)

Setting the belt tension on the 707-708-717 machines with the old rubber "Continental" belts:
1. Make sure that the hand-wheel spins freely on the main-shaft bushing stub when the release knob is loosened.
2. Assuming that you are using the original 441mm "Continental" rubber v-belts, the setting is made by means of loosening a 5mm Allen socket cap screw at the base of the step pulley support.
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NOTE: The hand-wheel, stepped pulley, and motor pulley v-grooves must be clean. This is to say, that they cannot have any particulate or threads wrapped around the grooves.
4. The pulley will be automatically pre-tensioned to a 7 o'clock position by means of a spring to maintain the stepped pulley position. By pulling the belt toward this 7 o'clock position, the pulley tension can be adjusted and then tightened by means of the fixing screw.
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5. It is important to know that both the upper and lower belt tensions can be independently adjusted so as to allow the hand-wheel to spin freely for bobbin winding without having the hand-wheel drive the machine. This is done by adjusting the step pulley support + or - radially, near the 7 o'clock position.
If the hand-wheel drives the machine with the upper belt loosened, then either the belt is too tight or the hand-wheel bushing and main-shaft stub need cleaning and lubrication.
Note: Lubrication was once the standard factory procedure with a class 68 oil, but experience dictates a dry lubrication with graphite. Silicone lubes are not recommended.
6. Do not over-tighten the 5mm Allen fixing screw as the 5mm threaded frame boss can be broken off.
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Adjusting with the original Polyurethane v-belts on models 807-801-810-817-811 machines:
1. Follow the same procedure as mentioned but allow the step pulley's positioning spring provide the belt tension. Nothing more is required here.
NOTE: Sometimes these belts and pulleys get oily thus allowing much slippage. A simple cleaning of the belts and pulleys with mineral spirits can solve this problem.
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After-market belts:
NOTE: One can find after market belts that serves to drive these machines but not without some problems as they are usually wider belts and don't fit the pulleys well. In this case some adjustment will be necessary.
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It sounds like your machine is set to wind the bobbin right now, so the drive is disengaged. That would explain why the bobbin winder pin is the only part moving. Check your manual for how to reset the machine when you are finished winding the bobbin.

Most machines have a way to disengage the drive for the needle while filling the bobbin. Then once the bobbin is filled, you re-engage the drive. Some machines have a separate, smaller hand-wheel that turns and clicks into place. Some machines automatically reengage the drive once the bobbin pin snaps into place away from the drive belt.

I hope this helps!

pull the 4 bottom rubber feet out and remove screws hidden in holes. Lift main body of serger up. you will see the gears. Probably drive gear on motor shaft got hot and slid on motor shaft.

Singer Online Manuals