Confused Parent trying to mod

[born2ride]

I have read the EAQ.. But need some clarification..  Two kids both wan to mod.. I have downloaded and installed forge on one pc fine. other one not so good.. I have installed the following mods on to the working pc ,Elemental Creepers,Archimedes Ships from minecraftmods.com  but they work sometimes and crash other times?? how come?

Question 2    Minecraft opens in troubled pc with tiny square in lower left corner.. Is the only caused by wrong java? says i am at 7

                3    mods  only work with certain version.??

                4    what mods can work with forge?

                  5  where to find them?

             

[born2ride]

Thank you for the reply ..  If minecraftmods.com is not a good . what recommendations  do you have?  I have tried so other site but was leery to continue DL  some showed suspicious files.

 

 

[loordgek]

http://www.curse.com/mc-mods/minecraft

http://bot.notenoughmods.com/1.7.10.html