Will restoring a late 2007 MacBook be a good investment of your time and money? Only you can decide that.
Keep in mind that 'good as new' will be in terms of 2007 performance, and not necessarily what you want or need today. Fixed and even upgraded with the maximum amount of RAM and a new HDD or SSD, it still will not be capable of running the latest version of OS X (10.9 Mavericks). http://support.apple.com/kb/HT5842?viewlocale=en_US&locale=en_US
It's still going to be a 7-year-old computer. And it won't be cheap for parts, even if you do all the installation yourself.
So, yes you can restore it. ifixit.com (and others) sell parts and have tutorial videos of how to do many repairs on a wide variety of Apple products. Other vendors such as macsales.com sell accessories and upgrades.
First, try removing the battery and run the computer only on the AC adapter.
See if your keyboard problem disappears. The user-removable batteries in thermoplastic MacBooks can swell with age. Swelled enough, the battery can distort the 'topcase' (which includes keyboard, trackpad, and palm rests) enough to cause keyboard and/or trackpad malfunctions. NOTE: If sufficiently swelled, once removed, the original battery can be difficult or impossible to re-install.
Now, if the keyboard now behaves normally, then a new battery might restore the MacBook to better functionality. You can purchase compatible batteries from a number of sources (eBay, Amazon, Apple) at a wide range of prices, and varying user experiences with reliability. From Apple, an original style battery costs US$129.00. That's unlikely to fix the screen backlight problem, though.
If removing the battery does NOT remedy the keyboard problem, it's going to get more expensive.
I still own a mid-2007 MacBook, and still use it daily, primarily for email and a bit of web browsing, but rather than continue to spend waste money on it, I recently purchased a refurbished mid-2011 iMac for most of my computing needs.
Message was edited by: kostby
