|That depends on the processing platform of your friends PC.|
Look here for explanation and decide which one is your friends:
IA64 - http://en.wikipedia.org/wiki/IA64
X64 - http://en.wikipedia.org/wiki/X64
X86 - http://en.wikipedia.org/wiki/X86 (X86 is most common)
Difference between x64 and IA-64? Look here:
How to find the operating system bit (x86/x64/ia64)
☺ When everything else fails, read the instructions.