For Example, you are installing Adobe Reader and also installing some other programs, chances are adobe reader will stop installing.
Some other programs requires a solo installation while some are not. Installing some application sometimes requires patience because some other application install requires more Memory than the normal programs running on your Computer. You have to consider also the "Specs" or "Specifications" of your Computer, the lower the Specs, the slower your Computer will be if you are doing multiple installs at the same time, and yet of course, be aware as I said earlier that there are some other installations that requires no other installations running.
If you are doing multiple installations at the same time, always monitor every installation because if an installation stops, do not click anything, finish the other installations first before you continue the "stopped" one.
Always read first before you click, you never know what other programs are included in the installation.