Good point LoyceV, what is at stake is the current value. Back then I had high hopes for bitcoin and tried to get others interested. When the value dropped I lost interest. myself I can see I made 5 transactions but can't remember what they were. And I remembered having printed the keys and put them somewhere. When I couldn' t find it I assumed I had thrown it away. Glad I still found it. 
Is it smart to put Electrum on a thumb drive, if even possible?
Make sure you keep track of where your change goes if you just import your private key.
What do you mean by ' change'?Is it smart to put Electrum on a thumb drive, if even possible?
Change is the money which is spent that returns to your wallet after a transaction.
Lets say you have 10BTC on an adress, you buy a new X for 4 BTC.
10 bitcoin will be spent, 4 to the adress for the stuff you wanted to buy, which means 6 will be returned to a change adress, ( hence the name).
If you just import the private key of the spent adress, ( where the 10 btc is ), you might not have access to your change adress, so be wary that you might need to change the change adress to an adress you have the private keys for.
Although usually this isn't the case, you should really check it before spending anything.