My pc does not boot on time and it hangs

Usually when I come across laptops that have this problem there are bad sectors on the hard drive. You should try booting into safe mode to see if you experience the same issue. While you are in safe mode you can a disk check through windows to scan the disk for bad sectors. Here's a guide:

http://support.microsoft.com/kb/315265

I usually just open up the command prompt and type: chkdsk /r

by itself. A big message will pop up saying the drive is locked etc.etc. just hit the Y key and then restart your computer. You will see a disk check message pop up. Just pay attention to it, if it takes a long long time then for sure you've got bad sectors and the drive is failing. Let me know what happens.

Best of luck!