OMG my head hurts after this thread. OP, replace the chain, the cassette, and the chainrings, end of story. 1/16" of an inch is the MAX your chain should reach before you HAVE to replace it.
This is from Sheldon Brown's website:
The standard way to measure chain wear is with a ruler or steel tape measure. This can be done without removing the chain from the bicycle. The normal technique is to measure a one-foot length, placing an inch mark of the ruler at the side of one rivet, then looking at the corresponding rivet 12 complete links away. On a new, unworn chain, this rivet will also line up exactly with an inch mark. With a worn chain, the rivet will be past the inch mark. [For accurate measurement, the chain should be held under some tension -- either on the bicycle, or hanging. Also, use a metal ruler or tape measure. Wood, plastic and cloth all can expand or shrink.-- John Allen]This gives a direct measurement of the wear to the chain, and an indirect measurement of the wear to the sprockets. first, let's look at how to do this with a ruler that measures in inches.- If the rivet is less than 1/16" past the mark, all is well.
- If the rivet is 1/16" past the mark, you should replace the chain, but the sprockets are probably undamaged.
- If the rivet is 1/8" past the mark, you have left it too long, and the sprockets (at least the favorite ones) will be too badly worn. If you replace a chain at the 1/8" point, without replacing the sprockets, it may run OK and not skip, but the worn sprockets will cause the new chain to wear much faster than it should, until it catches up with the wear state of the sprockets.
- If the rivet is past the 1/8" mark, a new chain will almost certainly skip on the worn sprockets, especially the smaller ones.
http://sheldonbrown.com/chains.html
In other words, you killed your drive train end of story. 1/2" wear? Jebus, its just like driving a car with only 1 quart of oil in the engine, it may run barely but by using only 1 quart of oil, you have ruined the engine so even after filling it back up to its normal 5 quarts, it will still be trashed.
Winter riding is the worst kind of riding you can do that will damage chains and drive train components short of actual hard core riding (mud/etc).
You will *have* to replace the chain, cassette, and chainrings for the bike to run well again.