We had very cold conditions in our area (-35) for about a week. I could barely get the car started one day. the next day the car wouldn't start at all. All the interior lights and bussers worked and the battery was fully charged. There was no sound coming from under the hood when i turned on the ignition. The starter is only a year old and was functioning just fine, i'm hoping it just a fuse but which one i don't know. Could it be the starter again? if it is a fuse which one inside or under the hood?

flassed less engine power wth????????? Flashed reduced engine power ! Electronic throttle control problem ! Your best bet ,take it to a GM dealer , buick , cadillac , GMC . You do not have diagnostic test equipment or knowledge to even diagnose this.

It is probably one of three things. It isn't getting a proper spark, proper fuel, or proper compression. Good luck!--------------------------------------------------------------------------
VAS 5054A

My best guess without being able to see the car is that the battery hard wiring is faulty.

You need to check both the condition, routing and security of the battery negative and positive leads.
You also need to check the security and condition of any additional earth leads which connect the engine to the chassis/body.

Could be the starter motor.

Make sure battery has a full charge.
Try cycling the ignition switch on and off several times before you crank it, to see if it helps. If it helps, check your fuel system. My info says fuel pressure, 35--45 psi.
How long since a tune-up? Any applicable trouble codes?

Check the anti-theft module and relay

READ THIS (happy ending so far...):
audi a4 2L turbo quattro, manual transmission with 98,000 KM. Perfect conditions, no oil leaks whatsoever.

Left the car off for two weeks in very cold weather (-10C down to -25C). When I restarted, it started immediately but with heavy rattling noise due to camshaft adjuster not getting enough oil pressure. After 3 minutes of warming up (outside temp.: -12C) at very low rpm (below 2,000rpm), I start moving the car. Still hearing heavy rattle noise. As soon as I pass 2,000 rpm, I get a scary red warning, low oil pressure. Turn off the engine immediately. In 1 minute, I re-start the car and the engine lights check ok, so I drive in first gear super slow (1,200rpm) hearing the same rattling noise. After another minute, finally the noise all the sudden disappears and the car starts running just fine.

Called Audi dealer and they told me that in extreme weather conditions, I should warm the engine for 10-15 minutes if necessary before start moving.
Take away: luckily, I didn't screw up the engine since I was using it at extremely low rpm (easy to do with clutch and manual transmission) until the oil reached full pressure. I am pretty sure now that the problem was leaving the car off for such a long time in freezing weather. All the oil flows back to the bottom, and when I restarted it, the cold oil with high viscosity took a long time to reach all the parts of the engine, specially the camshaft adjusters that are actuated by using oil pressure. Next day, the car started at -9C perfectly without making any noise (as usual). Basically, the longer you leave your audi in cold weather, the longer you might hear the rattling noise until the oil reach full pressure inside the engine. My car took 6 minutes to fix it after couple of weeks in cold weather. This makes sense to me; in fact, in the past I only heard the rattling noise after leaving the car off for a couple of days in the winter.
So far, this has had an happy ending....

My 2007 GMC Yukon will not start in cold weather. When I turn the key over the lights/dash controls come on, but the engine does not turn over at all. Nothing. Put a new battery in and still does it. It is a random occurance. Would not start for two days this week so I had it towed to the dealership and the next morning it starts without the service dept doing anything??? Bring it home and two days later it does it again??? Any ideas?

Yes, change the fuel pump.

I would try to jump it to see if the starter engages and the engine runs, if it does you have a connection problem between the engine starter and the battery, if it does the same thing with cables then you will probably have to tow it in to the shop. I do not think your problem is related to cold weather, but it could very well be related to the check engine light. Exactly what the check engine light is on for I can not say with out a code, but I agree with your thinking about taking it to the shop. Hope this helps, let me know.