Solution for invalid directory item count, startup disk corruption and regular crashes

Hi,

My late 2006 MacBook (10.6.8) has recently started crashing quite frequently. The screen becomes dark and a multi-language dialogue appears stating that the computer must be restarted with the power button. When this occurs any audio which was playing begins to repeat/skip and the computer goes into complete lockdown. This is now happening perhaps twice a day or more under moderate use.

This morning I ran 'Verify Disk' in Disk Utility and the process was stopped, stating that I had two 'Invalid directory item counts' and 'the volume Macintosh

HD was found to be corrupt'. Here is a screenshot of the Disk Utility window:

I have rebooted, run a software update and rerun the disk verification but to no avail. I also booted using CMD-S, advised by an older post in another forum which suggested using 'fsck -yf' which ran and stated that the disk had been repaired.

I bought the MacBook second hand from an Apple dealer but it didn't come with an install disc so I am unable to reboot and repair the disk like that.

My questions, therefore, are what does this mean for my computer in the future, will either of these issues cause me more trouble?

What can I do about it without the install disc

And are these issues directly related to the crashes? (I have been running the computer connected to an external drive and monitor - for watching movies)

Thanks in advance for any help you can offer!

Twitch