Either you should have copied the wrong wallet.dat file as others said or you should have done something wrong while importing the file to sync with the newer version of the core wallet. If you have messed up with the wrong wallet.dat then you have lost your btc probably. If you are aware of the addresses which holds your money, try checking out in a block explorer so that you should make sure you haven't lost them forever.
If you have the same wallet.dat from the corrupted computer that still holds $2000, then after installing a newer version of OS and qt client try this to retrieve your coins
1. Download a newer version of core
2. Run the wallet software
3. Once it starts running, close it
4. The client should have created AppData folder in your Roaming folder
5. Replace only wallet.dat file with your older file
Since the wallet.dat is not a human readable file, you should export your private keys if you are willing to create a paper wallet
6. Restart the core, go to the console and type
dumpwallet [filename]
This will export the keys associated with the wallet.
7. Allow them to sync if you are gonna use core
Note that, you should close the client and replace the wallet.dat file with the older file. That's how it should be done as far as I have read.
There might be a chance that your wallet.dat could have crashed along with your computer. If so, try having a copy of the wallet.dat and replace them and run the -
salvagewallet command. This command will help you in recovering the private keys associated with the wallet. Running this command is quite risky since there are chances that this will corrupt your wallet.dat file even more. Hence try this command when you don't have any other choice of recovering them. Also save a copy of .dat file prior trying this out.