1. I want to move bitcoins from a QT wallet to electrum (I know imported wallets cannot be recovered from seed). I want to import just one of multiple private keys. I was under the impression for every private key there were 100 addresses. I don't have that many addresses but I have more than 1 private key. I know how to use QT to dump my private key for a specific wallet address, if I import this into an Electrum wallet and then transfer do I ever run the risk making my other private keys in my QT wallet unusable? I do not want to use the command line but I would rather not expose the entire wallet if I can keep 90% of the balance in cold storage this way.
2. I know electrum wallets are deterministic. Does this also mean that if someone knows an Electrum address of mine they will also be able to determine my other electrum addresses and in turn my entire wallet balance for that electrum seed?
3. I know that using java in your browser is a risk. If it is the only real risk you take is it possible to get a virus from Java script or the recent heartbleed bug/QT version 0.9.0 which could infect the computer's BIOS? Since I cannot flash my BIOS, I am worried about putting the computer online again before flashing BIOS and zero filling the hard drive.
These are real tin foil hat questions for the small amount of bitcoins that I have but if I lose them it will be devastating. My neighbor who I don't trust knows I have some bitcoins and he is a programmer. I appreciate any help
First off I take it you accidentally made a self-moderated thread since you're just asking questions.
1. Incorrect, each private key corresponds only to a single private key. You'll have to import each one that contains a balance in it. Alternatively if you want to take use of Electrum's deterministic system you'd need to send it to one of the generated address rather than importing as imported keys aren't restored from seed.
2. It doesn't matter if they have your address - it's designed to be public and shared. What you don't want to is to expose the 12 word seed (e.g eat burgers potato nuggets etc) as all the addresses can be determined from there.
3. Java =/= Javascript - they are completely different things that have different features and functions. As far as security goes, being paranoid is good but it's a lot of effort. For most people making sure to scan their stuff with an AV and not clicking random links plus having an encrypted wallet is enough. For those worried about leaks in RAM then they may use a cold storage solution but it is a bit more effort.
Best advice is to keep you're wallet encrypted. No one not even the NSA would be able to bruteforce the encryption hence you'd be fine (except if there's a hole in the implementation - but there are bigger concerns if there are).
If you need any more help feel free to ask.