Ran chkdsk from cmd

Hi all, I had posted that my system crashed on me and I couldnt read the blue screen before it restarted itself, so I decided to run chkdsk/f/r C: from cmd, I restarted, I see my HP logo come up, I see the aura screen, then the screen goes blank and my HD is lit...I understand that chkdsk can run for hours.. but I'm not sure its running at all...theres nothing on the screen, no options came up...I dont know if I screwed something up, I'm going to let it sit like this.. (i've been up since 2 am so I'm crashing..) if its still like this in the morning, my question is...how do I cancell this? It was set to run at start up in cmd prompt because the drive was in use when I tried to run it from cmd prompt. Is editing the registry the only way to fix this? Can I boot to safe mode to do this editing? Is there a listed procedure for the editing somewhere on our site? I need some help all.. thanks for your responses....

ok.. an update. I got up this morning and chkdskran its course. I havent found the log file it must have made, there was no messeges when I logged on and my desktop came back up. But I need to know how to cancel the chkdsk operation on start up. Can anyone give me an idea?
Oh and I did finally remember that I had changed my boot screen options so all I got was the blank screen as chkdsk ran, that was why I couldnt tell if it was actually running and what it was doing, and I need to stop the automatic restart when it crashes, I'd rather see and read the screen before I restart from BSOD.