I have a 5 1/2 month old girl pup. She is an Irish Setter. Her house training went fairly well considering she was born here - always more difficult to house train a pup in the home she uses as a toilet for the first few weeks! This last week though she has peed on my bed twice, on the floor several times and poo'd in the house several times also. I know what to do about it - go back to basics and start taking her outside again and rewarding but I wondered if anyone has an idea why she has started doing this? Nothing has happened to upset her, nothing has changed that I can think of. There are no signs of an infection. It's weird.

Some pups tend to forget, other do it on purpose.

My pup is nearly 8 months old and still not house trained *rolleyes*
He was doing really well, but then the weather turned cold and he started going inside.
He knows it's bad because he usually finds a corner to hide in or disappears down the hallway.

I'd just start from scratch, take her out every hour or so like you would a baby puppy. She will get the hint eventually, she might just be either a bit slow, or a bit sneaky.
I don't know what you do as 'punishment' but she's at that age where she needs to learn that what she is doing is not good (if you catch her in the act of course)

Thanks Shazamataz. In reply to your punishment question, I don't punish in housetraining as I have found that if this is done, all you end up with is a dog who hides away before doing his toilet indoors. The reason being...
pup 'goes' indoors in front of you = bladder relief & punishment.
pup 'goes' indoors out of sight = reward of bladder relief and no punishment (as you say, pup cannot associate later punishment with deed).
pup toilets outdoors in front of you = big reward of bladder relief and treat/praise and no punishment.
pup toilets outside alone = reward of bladder relief and no punishment.
A punished pup will work out that his options are to either go outside or to go inside but out of sight. This is something I teach everyone who buys one of my pups because there is nothing worse than finding smelly presents hidden around the house! Having said that, I did push pup off the bed when she was weeing because I really didn't want it soaking through to the mattress - yuk.
I think perhaps I haven't put enough work into her housetraining or I must have relaxed too soon. Her older sister learnt to be clean almost entirely from the older dogs, she housetrained so early I wrongly assumed this one would be the same. I know what you mean about cold weather, mine don't like to go out in the rain the awkward devils

Keep at it, she will understand eventually. Might just need to invest in some good cleaning products ;)

I agree with the punishment and then going out of sight but when mine goes inside I usually give him a growly NO and rush him straight outside.
I have tried the 'nice' approach and taking him out every hour to no avail, I'm at my wits end on this one... they can be known to be 'dirty dogs' though *sigh*