someone sent coins to the wallet address, gave me a tx number that I stuck in and hit receive
Could you explain what do you mean with this? You don't seperately hit any "receive" or "accept" type of buttons if the transaction has already been sent/broadcasted to the network. An exception is that at least with the current client, you are able to create a custom request for a certain amount for example if receiving payments from different clients.
left Bitcoin demon running ( It probably didn't sync with the network) and went to work.
Even if you have not synced the whole blockchain, the transaction should have been broadcasted within matter of seconds to the network. At that time mempool was pretty empty i guess, so it should have not been dropped from there either. However im not certain if the early clients did that as well, or if you had to sync the whole blockchain before sending. At least the current versions send them to nodes anyway.
When I got home the power had been off and the computer was off, I never had it back online since then. I looked on the block chain at old addresses and don't see that amount around the time it happened.
Are you sure that he actually sent everything to you? Probably not if you cannot see it in your wallet nor any block explorer.