MacBook Pro Yosemite Install Issue with Disk Repair Utility

I'm new to working on Macs and I've had some trouble.

My MacBook Pro was running slow, the fan was always on full blast, it stopped recognizing the battery, and the LED wasn't lighting up when I connected the charger.

So I tried upgrading from OSX 10.7 to 10.10, and the disk repair utility failed on verify disk, and repair disk, it returns exit code 8, and it won't let me return to the earlier version 10.7, just states that not enough information could be gathered from the selected drive.

Any advice on what might be going wrong and how to fix it would be greatly appreciated.