I had a dog that we treated with Panacur for Giardia and it worked also.
That was after we had tested negative with one test. The diarrhea continued and the vet sent a second sample to another lab and it came back positive and then we treated both of my dogs with the Panacur C.
I know that first she was treated with Metrondiazole and then Panacur C. because she was older and the one with the infection, however, my younger puppy was just given the Pancur only.
Good luck to you, I hope you get the problem resolved!

Update:

Well after speaking to the vet, we decided to just treat her with the Panacur and it didn't work.

We had sent in a stool sample to the vet when she arrived home from training with the breeder to check for worms. The test was negative. On the phone, the vet said that he didn't believe that she had Giardia because it would've been found in her stool sample. I said that I thought Giardia was hard to catch unless a stool sample was taken directly from the dog and he said that they tend to catch Giardia often in a regular stool sample. I asked him what he thought she might have and he didn't have any response other than he said it would be best for him to examine her.

Based on that, we decided to just treat her with the Panacur first since we had already gotten some from the breeder. We gave her a 4-gram dose each day for three days over the weekend. Unfortunately, the pudding diarrhea still persists.

One last thing we're going to try before taking her to the vet is switching her back to her old food. She was eating Taste of the Wild kibble before and we switched her to Royal Canine German Shepherd formula, mainly because she inhales her food and I liked the bigger kibble that the Royal Canine food offers. I'm crossing my fingers now that this is all because of the food switch (maybe the bag had some bad kibble in it?) and switching her back will get her back to normal. If not, we have an appointment set up with the vet mid-week.

I just realized you had sent your girl back to the breeder for 2 weeks and then she came back and her feed was switched.

Hmmmm...wondering if food switching AND home switching may have triggered a tummy?

Go back to original food = good idea...if she eats too quickly, stuff some large rocks in there...unless she chews rocks of course...to slow her down.

Then, keep an eye on her and stick to your plan. Sounds like a good one.

You have switched your dog from a high quality, grain-free kibble to a lower quality, grain-heavy formula.

No wonder her system isn't happy! Dogs were never meant to eat bowls of cereal.

Give her better quality food for a better quality life.

Edit:
Royal Canin "German Shepherd" (lol) formula: http://www.royalcanin.us/products/productdetail.aspx?ID=35

Taste of the Wild: http://www.tasteofthewildpetfood.com/products/

Another update:

So we switched her food back to her old food on Monday, but her diarrhea was still pudding like. We got her into the vet mid-week. By then, her stool was more like a cow patty, semi-solid coming out, but cow patty-ish once it hit the ground.

The vet (a different one from the one I spoke with over the phone) did a rectal exam on her, took her tempurature, etc. and ended up prescribing Metronidazole. I was happy about this since I've heard this was common to treat Giardia.

We gave her her first dose of the medicine (which she hated, she kept spitting out the pill no matter what we tried to wrap it in!) and she had her first solid log poop the next morning. So happy we're finally past this! Plus the yard was starting to get really nasty. :-)

 Quote: sharon eliot

We gave her her first dose of the medicine (which she hated, she kept spitting out the pill no matter what we tried to wrap it in!)

I had the same problem getting my dog to swallow any kind of pill. She had to be on antibiotics for three weeks!

Someone one here suggested (can't remember who, but credit is given) that I put it in a blob of butter. Worked like a charm.

She would lick it right off my finger and started looking forward to her "butter pill" twice a day.