[specific priv key for a cold storage address 'A']

Hello all in my understanding of wallet.dat is that it contains the keypairs belonging to all "addresses" that a wallet eg . bitcoin-qt/core randomly generated upon creation of the wallet.? (100 addresses for qt?)

what I'd like to know is how the bitcoin pros out there find your "specific priv key for a cold storage address 'A'" within your wallet.dat..?

for example...i have read threads where people spoke of etching their "priv keys" on tungsten blocks or other really creative methods of long term unburnable storage of priv key. im assuming they somehow enter into their wallet.dat and identify the specific private key for their address?
can anyone elaborate?

thanks all for your help

[sell and realize a loss]

my wallet operating system was deleted and i made no backup so my bitcoin is lost.....Can i claim a tax loss?? i figured losses can only be claimed when you sell and realize a loss...how do i prove i dont control the coins....and even further how do i prove i lost my priv keys???.(why dont all US bitconers jus claim losses and when the day comes bitcoin hits the moon jus sell your coins then)
thank you

hello all ...newbie here
i have grown accustomed to the generate new address option on the 0.8.6 satoshi client and it prompting me for my priv key to generate them...having recently upgraded to 0.9.1 in my noobishness i cant seem to figure out how to generate new addresses...         so here i am in the beginners & help sub-forum

thank you all in advance for your replies

Hello all...newbie here i currently have ubuntu 12.04 and i sucessfully upgraded my openssl version to "built on" date of apr7 2014. however i have been unable to find any suitable guide to install new qt 0.9.1 on my ubuntu os and im still using the .9.0 qt..was upgrading my openssl version sufficient or are there more steps for me to take to ensure heartbleed is fixed?

Thanks

hello all..i have been a lurker on these forums for awhile and have recently decided to buy some btc during the last downtrend...i used the bitcoin qt 0.8.6 and had it on an external ssd...my friend was reformatting my computer and as he was trying to create a partition but he deleted my ubuntu OS which had my wallet software on it...i procrastinated on backing up my wallet.dat equivalent file on linux..all i have is my private key and my address where my coins reside..is there any way to recover my btc or are they lost forever??
thank you all in advance.