Hardware components based on which to generate password

On windows, you can use the DPAPI to protect your keystore and ensure that the data can be decrypted only on the machine on which it was encrypted (or if you want, by only the user that encrypted it).

This will be a more straight forward approach than trying to generate a hash out of hardware information, will provide the same (or better) degree of security and will have less chances of making a mistake and would also avoid the problem of hardware changes resulting in data loss.

1. If you were on Linux, you could simply query /dev/urandom to get the random value without carrying about what the source of the randomness exactly is. But yes, the device will use noise generated by the devices to increase the entropy.
2. On Windows you may use the Windows equivalent: https://stackoverflow.com/questions/191335/windows-equivalent-of-dev-random
3. But you may also use everything else that is meant for crypto purposes. You have tagged your question with [java]. In Java you may use the SecureRandom class. The output is unpredictable and this should be the most important concern regarding a random number generator.