Long CHKDSK A Problem?

My 400G drive in my P4 has been in CHKDSK mode (from the XP prompt “What to force a scheduled check on reboot?” from computer management) for over 12h and is at 46%. Is this okay for a 400G drive, or is this puppy getting cooked?
This PC has crashed on me so much since Nov, that I was forced to format in Jan. Now I am getting errors all over again.
I had done a lot of these checks in the past few months and took almost as long at times. Using all the tools on the Ultimate Boot CD, none found problems with it except for all the corrupted software, forcing that format. Actually, I ended up having to wipe the entire partition with FDISK in Jan.
Thanks.