Lost lowest gear!

[citybabe]

I had a puncture in the rear tyre so removed the wheel and changed fixed it.
Now I've put the wheel back in I've lost 1st gear - can't get the chain to stay on the cog.
The chain is a bit jumpy on the cassette rings as I move up and down the cassette.
It seems as tho I've moved the gears along somehow as when in 7th chainring there's another click up on the gear shifter without the chain moving along.
The bike is a Raleigh Pioneer with 14/28 freewheel and 48/38/28 chainset.
The wheels aren't quick release wheels. Is it possible that the wheel isn't in the drops correctly?

 

[mcshroom]

Sounds likely. Take it out and put it back in carefully and hopefully it'll right itself

 

[TissoT]

When you put the wheel back ... put the chain on the highest no1 gear
If it starts to jump out/down .. Then its possable the cable needs adjusting via the thumb turn Adjuster onto of the rear mech !