Windows 8 slow boot time

I'm having issues with my Win8x64 desktop box. The problem is that every 4th or 5th boot, windows just hangs at the boot screen for about 3-4 minutes without any activity(at this point i can see the num lock key blink multiple times) & then the loading indicator comes up & everything starts normally. The rest of the time it just boots up without any delay. I don't use any AV & I've also disabled the built-in AV. Is there any way to find out what is causing this delay?

event viewer.

My question is; why are you having to reboot so many times? Try running sfc /scannow in a cmd prompt to see if it finds any missing or corrupted files. If it does it will try and repair them.

Event viewer has not been of much use.. nothing interesting there.. I run chkdsk on a weekly basis before defragmenting my drives, so i don't think that's the issue.. Well, i have enabled boot logging for now.. let's see what happens the next time.. btw can someone confirm the location of the windows 8 bootlog folder/file?