1. If can afford the space, copy the Bitcoin blockdata to a backup location before deleting it (blocks and chainstate folders in your Bitcoin datadir). Your Bitcoin datadir is "C:\Users\<MY_NAME>\AppData\Bitcoin"
2. Delete the databases folder from your Armory datadir. Your armory datadir is "C:\Users\<MY_NAME>\AppData\Armory\"
3. In your Bitcoin datadir there should be a bitcoin.conf file. If it's missing, create the file as plain text using the Notepad. Make sure the following lines are in it:
server=1
blocksxor=0
prune=0
4. Start Bitcoin Core (either bitcoind or bitcoin-qt), let it download the chain. Note that you will need some 600GB of disk space for this. Aim for 700+ to be safe.
5. Once Core is done, start ArmoryDB from the command line, let it do its thing, will take from 30min to a few hours. Leave Core running, ArmoryDB will find it.
6. Once ArmoryDB is done (it will tell you something about zc parser threads), you can start ArmoryQt. Leave ArmoryDB running, ArmoryQt will find it. This will start the scan process, will take from 10min to an hour. Once the scan is done, you should see your balance and transaction history in ArmoryQt.