That's the one! I show this as being a "MacBook (13-inch Mid-2007) model".
There are two common possibilities for this issue.
One is that the internal memory has become defective or loose. You can check if it is loose yourself using directions via the following link for your model:http://support.apple.com/kb/HT1651#link3
Remove the memory, then re-install it and try the fsck procedure again. If there are two memory modules installed, try leaving one out for testing (and then test with the other swapped in next).
If memory does not seem to be an issue then there is likely a severe issue with the hard drive, this could be software or hardware but it will be difficult to eliminate without an install disc.
It is no longer officially sold in most stores and if you can't readily find it most customers have been able to get it from Apple by ordering online or via telephone.
For a limited time, it may be available via the Apple Online store in the US:http://store.apple.com/us/product/MC573/mac-os-x-106-snow-leopard
Call 1-800-MY-APPLE (1-800-692-7753) and tell them you want the Snow Leopard upgrade which they can send on CD for around $20 USD shipped.
If you do not feel comfortable checking the memory itself or wish to spend money on the CD then the next option is to contact a local authorized service center.
When troubleshooting hardware issues, sometimes the final diagnosis is that it is a physical defect in nature and the ‘answer’ such as in this case may be a recommendation to seek out repair from an authorized service center if the defect in question is not considered “user repairable”. This may be a frustrating answer and I do sympathize but please don't shoot the messenger.