Restoring my laptop to original factory state.

I have an ASUS laptop that has started running slow even tho I have run cleaners and virus scans etc. I don't have anything on there that I am concerned about losing. (Pictures, downloads etc.) I have decided I want to wipe the computer clean except for the Windows 7 operating system. I have burned a Windows 7 repair disk,. but have no other disks that came with it. I do have the product key for the OS.
How do I wipe the hard drive clean and reinstall Windows 7?

I do have a good link to a torrent of Windows 7 Home Premium 64 bit addition. Which I assume I need to download and burn to disk???
From there,. what do I do to format my laptop to it's original factory state or with just the Windows 7 OS?
Any info would be greatly appreciated. Thank you in advance!

I downloaded the ASUS recovery instructions as you said to,.. and after it says to enter into Windows Setup and follow the ASUS preload wizard,.. the instructions say to select a partition option and click next. 4. Select a partition option and click Next. These are the options it gives me.
Partition options:
#1 Recover Windows to first partition only.
This option deletes only the first partition and allows you to keep other partitions, and to create a new system partition as drive “C”.
#2 Recover Windows to entire HD.
This option deletes all partitions from your hard disk drive and creates a new system partition as drive “C”.
#3 Recover Windows to entire HD with 2 partition.
This option deletes all partitions from your hard drive and creates two new partitions “C” (60%) and “D” (40%).

Which one of those should I select?

I only have one.

ok will do. I'll let ya know how I make out. (If it all works and I can get back online. lol)
Thanks for your help.

It worked great. Thank you Yard dog!