Shane will know which file to copy over from your other computer if need be but if the drivers don't do it, you could try to see if MS will accept your product key to download the ISO.
You can try with the sticker key but also with the vendor's generic key if that doesn't take.
Belarc Advisor will list that for you.
http://www.belarc.com/free_download.htmlEnter either key into
http://www.microsoft.com/en-us/software-recovery and that will determine the version it will download if it accepts the key after selecting the language and you select Save.
The download is 3.09GB so can take some time to download depending upon your bandwidth.
The article also includes a link for the Windows USB/DVD burner tool to create the bootable media of your choice to match what you computer can boot with before the HDD.
You may find an alternative vendor key among this lot if they don't but you could have a look at that video to see if that will help - I've never viewed it yet so don't know how useful it will be.
http://itstrickszone.blogspot.co.uk/2014/01/windows-7-all-product-keys.htmlIf you manage to download and create the SP1 ISO install disk, these are the steps to perform the MBR repair.
http://www.7tutorials.com/command-prompt-fix-issues-your-boot-recordsYou will need to change the Boot order by tapping F12 (usually) as you switch on, select and insert the media and then press enter.
You'll be prompted to press any key to boot from the media and when it has loaded, you may be presented with a black screen with options to press F8.
After you've pressed F8 select Safe Mode with Command Prompt.
You should eventually be presented with a blue splash screen where you select Repair your Computer to navigate to the Recovery Environment where you select Command Prompt and then you can follow the steps in the article.