If it runs for more that about 5 minutes on each run, there is probably something wrong. The only time I have seen it run much longer is when it was trying to repair a system that did not have an active partition.
Why are you running it, system would not boot and what message did you get?
Have you changed any drives in your system lately or changed the Bios boot device list?
windows failed to start launch startup repairwhich they said was reccommended or start normally, i tried start normally and it went to start up repair anyway. did do change anything at all on the last shut down
When this type of situation occurs, it is almost like you need to flip a coin to see what might be wrong. I would say most of the time it is because of a driver being installed that is causing problems, but no way to know for sure.
Can you get into the F8 menu and select Use Last Know Good Configuration, or boot into Safe Mode?