windows verification/or bug / system file question

Hi i have this question for all ,

the back ground

the computer that i use , is a non registered Windows w/out a license
i know before anything may say anything i know i don't like it but its not mine its a family members and is built by a friend of a family member who deals with computers and well the so called software that he gets, everything is fine but i cant up date anything ,makes me nuts and i want wait to go out an get the real stuff and some day i will when i have the money,
any how its a XP system

my question

does the Windows verification software plants bugs in ones system to shut down any non legit /copy guarded or and so on files?

a few months ago i would have files running like an older game file like one called Mario.exe an old Mario game that is 60 KB in size, but now it wont run even if i set the compatibility to win 98/win me and so on in other settings and still wont run

also one of my moms brothers also said that that windows verification program will plant bugs or do harm to files that are not legit or software thats don't have any copy guard, but it shuts down or does something so old and odd programs wont run again, is this true? ,and what can i do or look for to reset the system to make those old games and other files run again

does anyone have any idea how i can fix them or make the system right to run those files again , and thanks for any help :confused