Question about recovering old bitcoins..

Hello,

I recently found my wallet on an old HD (Windows XP) and mounted it on current machine Ubuntu (Mint 15 with 3.12 kernel fwiw)...

It appears the mining client I used at the time isn't installed on that XP partition anymore but I found the entire APPDATA folder including my wallet.dat

I installed Bitcoin-qt from the repository, replaced the new/blank wallet with my old wallet.dat, then I ran the command "bitcoin-qt -rescan". After downloading the block for approx 12 hours it showed a green checkmark in the lower right hand corner, but my balance still reflects 0 BTC.

I don't know how I should approach this at this point. I assume my wallet could(?) be encrypted and I need to remember my password? Is that what I need to use the python tool to manipulate my old wallet.dat? Is there an easier way to go about this without risking screwing it up somehow?

I have backed it up to several USB and am only working with the file on a VM right now..

Thanks in advance for any input/help,
c