Bob - Ubuntu was the first distro I tried because one of the staff at PN advised me to use Wubi.
I wasn't enamoured of it at first whereas with Mint, I liked the look of it instantly.
However, there was that little glitch which irritated me, but the main reason for changing was that there is just something simple and straightforward about Ubuntu that I now like. It seems to me that everything is where it logically should be and can be found qjuickly and easily. I like the separate categories and the top toolbar - not so keen on the Mint menu.
Also, there is a great deal of documentation and support for Ubuntu.
http://www.ubuntupocketguide.com/index_main.htmlThe above link is the Ubuntu pocket guide which is full of information.
There is a little quiz on psychocats
http://www.psychocats.net/ubuntu/ which points you to the most suitable distro for your needs. Did it the other day and it came up with the Debian distros - Ubuntu at the top 100% with Mint a bit further down although still scoring highly so it is really down to personal choice.
From what I have read, Biker is, of course, correct - Xubuntu is recommended for low powered machines. Have run it on a live CD and it is quite straightforward and very like Ubuntu except for the XFCE desktop.
I think that Puppy is also suitable - have tried it briefly via live CD and that is all so no real knowledge of it.
Installation of Ubuntu is not as intuitive as Mint (it seems to me) but you shouldn't have any problem as you are using the whole disk anyway - a distinct advantage.
With regards to Compiz it's nice but might be best to get used to things first and explore that when you are more comfortable with things.
Glad you got the Help thing sorted - didn't think of that as it all came complete when I used Mint - wonder if it is something to do with the download location?