PC won't boot when the room is cold

Hey guys,

I recently got some problems with my computer if I try to boot in a 'fairly' cold room. It's like 15 degrees celcius when I try to boot, and I have to reboot like 4-5 times before it actually gets into windows. After the computer is booted it runs like a charm, no lock-ups or anything, and I can reboot as much as I want without any problems. The problem only occurs when I leave it off for a while (like when going to bed), and trying to boot in the morning. The funny thing is, since I know it has something to do with the temperature (since it boots like a normal PC in the summer), I tried a hair blower/dryer while aiming at certain components. I tried te PSU, HDD, Memory, but none of those actually made any difference, untill I pointed the hair dryer around my CPU. I have an EVGA 780i mobo, so the nforce chip is right below the CPU. It's pretty hard to aim directly an the CPU, since I got a thermalright extreme 120 cooler being huge on top of it. When I do this for +-20 seconds, and I try to boot my pc, it boots like it's summer. Do any of you guys have any idea what could cause this? I usually like the cold weather for OC-ing, but in this case it's starting to annoy me.

I'll list my specs below:

Q9450 cpu @ 3.5ghz (doesn't seem to make any difference with the cold boot when I run it on stock settings)
EVGA 780i mobo
OCZ 800mhz sli-ready memory
MSI GTX295OC
2x 1TB spinpoint f1
Thermaltake 750watt Tough Power PSU.

Any advice is welcome, since I'm kinda running out of ideas.

Thanks in advance