My girlfriend's cycle is usually 31-35 days, we had protected sex on her 29th day of her cycle. now she is 42 day no period. how likely for her to get pregnant from what i have stated above?

It is possible. There have been pregnancies reported from exposure on any day of their cycle, including during menses. There are unusual but possible. I consider no days in a woman's cycle "safe" for unprotected intercourse unless you don't care about possible pregnancy. OTC urine pregnancy tests can usually detect pregnancy 2=3 wks after exposure.