Will a MacBook Pro Early 2011 installation disc work on a 2007 or 2008 MacBook Pro 15?
No it will not.
Machine specific gray/back disks are for one model of Mac only as they only contain hardware drivers for that model, not previous ones.
The 10.6.3 white Snow Leopard retail disk will work and it's available from Apple online for a small charge.
My collegue's 2007 or 2008 Macbook pro 15 inch keeps getting stuck on the apple load up screen everytime he hits the power button.
I tried safe mode, it worked but after the loading bar gets close to 1/2 it freezes up.
This is indicative of a problem with the boot drive and the file structure retaining data on the drive.
The progress bar progressing and stopping means the fsck drive repair is failing, likley the drive incurred head shock damage at that point.
The boot drive itself is likely fine and the problem can be resolved but the disks are going to be required if it's running Snow Leopard.
First get the disks, then attempt Disk Utility > Repair Disk and check the SMART status if the drive is still good.
If there is no backup of data, get that off the machine using a external boot drive.
To fix that problem of a bad sectors, unfortutly the entire drive will need to be Zero Erased (security option > zero all data) using Disk Uility while c or option/alt key booted from the 10.6 disks (using a wired or built in keyboard), it's the only way.
This means all programs, files (remaining) and OS X will be removed in the process. You could replace the drive also.
Step by Step to fix your Mac
Create a data recovery/undelete external boot drive
How to erase and install Snow Leopard 10.6
Install/upgrade RAM or storage drive in Mac's
https://discussions.apple.com/community/notebooks/macbook_pro?view=documents#/?p er_page=50
