I’ll keep from creaming about ‘Cloud’ (I won’t use it).. but, as for your older laptop, since you already have experience on Linux, I would highly suggest you using XFCE on it. Very low resource use...
As for your current PC that is running 12.04 LTS, I think you meant 32 Bit instead of 64 Bit (has nothing to do with your RAM, but a x32 will not go over 3.95 Gig of your RAM, if you have more).
As for a Virtual... you should be able to find and install Oracle’s VirtualBox on your Ubuntu. I have Win 7 on 1 screen (running in Virtualbox) and my normal Mint KDE on the other.
Trouble with typing when it is that early in the morning. Yes, I meant a 32-bit bus with 4GB of RAM.
You cannot count the number of times over the years I've kicked myself for building a 32-bit system. In theory, running a Virtualbox instance would be ideal for a lot of the stuff I want to do, but, sadly, I seem to max out on resources far too much.
Need to save some money up and build a more up-to-date system.