1995 Ford Fiesta no power in the gears

1st gear is the strongest gear to use in cars and to use the other gears with no power sounds very much like the clutch or no compression in your engine.
1. To test your clutch, put the handbrake full on put it in first gear and slowly let the clutch out. If the engine stalls then your clutch is ok.
2. Feel the travel on your clutch pedal, if it is higher than usual it means your clutch is wearing out.
3. The compression on your engine could be the problem. To test your engine compression, take off a plug lead one by one replacing the one you took off first. If your engine still sounds the same when the lead is off it could be the compression on that cylinder. replace that lead and try the rest. Engine should sound rough when a lead is removed. Use an insulted pair of pliers or you will end up with a shock.
4. Other theory, remove your plug lead and hold it about 2mm or 1/8th inch from the plug and you should see a spark, if no spark, then renew all plug leads. Also, try removing a spark plug one by one replacing them as you go along, hold the plug with insulating pliers again and touch a good earth point and the plug should spark at the electode.
5. If all above is good then I am afraid your balk rings in your gearbox have worn out. These give you a smooth gear change and its called a synchronised gear box. Sorry. The Fonz.

having loss of power with my car can these rings on the gearbox cause the effect of poor performance only when engine is up to temp, as before that when cold my car runs fine, 1.8 duratec mondeo mk3