MY MAC WON'T BOOT. PLEASE HELP!!

Hello,
My MacBook was freezing, so I tried ForceQuitting the application, but it took too long.
So I took the battery out, thinking it was going to be the fastest way. But unfortunately, when I put the battery back in, and tried booting it, the hard drive starts making noise and a light blue screen would come up.
I think this is happening because my hard disk is too full. My hard disk has the capacity of 111GB, and only 6.8GB are free now.
But I can't even start it up so I can erase some of it, what can I do???
PLEASE HELP ME!!!!

I'd really appreciate it. Thanks:)