1545 Dell Inspirion index checking errors and freezing

My 1545 Dell opererating Vista Home Premium keeps freezing constantly. I am running firefox.  Never had issue before.  It crashes, I reboot and then it goes through a error check and here are some of the messages

1) NTFS needs to be checked for consistency volume label OS

2) Verifying indexes and deleting sessionstore.js $130 of 66724 (this is message everytime probably done 25 restarts over few weeks)

3) USN journal update

Then I sometimes get a blue screen with

1) Kernal stack in page error through index checking OS SYstem

2) Load dump NTFS OS volume label OS

Can anyone please advise what this might be. I have read another post where the same PC having same issues where the memory is not being cleared properly and the issue remained even after loading Vista.

Thanks

Mandip