What didn't get backed up?

[MC Matt Cooper (2838)]

Hello allo,
    We have a few Windows XP PCs in Payroll that have some special
software on them.  So I am to use our TSM 5.1.8.1 server to backup thes
PCs (TSM client 5.2.0.6) with no excludes.  Normally we only backup a
very specific directory structure on a PC.  So thinking that it is only
a few PCs I will backup everything.  It inspecect 26,009 files but only
backed up 23,511 files.   What didn't get backed up?   Will I be able to
restore installed software?
Thanks in Advance
Matt