I've salvaged my old netbook with Windows XP and have been able to access a couple of Bitcoins that a friend sent me back in 2011 (!) when he was getting into this new cryptocurrency thing. BTC was beyond my skill set then and just out of reach now -- the wallet.dat is running on Bitcoin Qt v. 0.8.5 beta.
The coins have 155140 confirmations but Qt is running 162 weeks behind -- it takes forever to load, and will never catch up to the network on this ancient machine (have kept it running for days now) -- would like to move the BTC somewhere else -- have tried sending a test amount (0.01 BTC) to a new Mycelium account on my phone but each time get this error:
Runaway exception A fatal error occured. Bitcoin can no longer continue safely and will quit. St13 runtime_error CDB() can't open database file wallet.dat error -30974
Am at a loss what to do next -- any help or straightforward advice on what steps to take in order to move the wallet.dat to another machine for an inexperienced Bitcoin layperson would be most welcome...
First of all if you have not done it yet, I would encourage you to make a backup of the wallet.dat file (e.g. copy it a usb stick).
One solution would be to let bitcoin-qt show you the private key for the address for which you received bitcoins back in 2011. Then you could import (actually "sweep") them with Electrum. See the following help: https://en.bitcoin.it/wiki/Transferring_coins_from_Bitcoin-Qt_to_Electrum
This should also work with version 0.8.5 and you don't need to wait for bitcoin-qt to have downloaded the blockchain or anything.