best way to refresh - restore a late 2008 Macbook Pro to factory settings.

I have a weary and semi sluggish Macbook Pro (late 2008) that I just reclaimed from my college bound son. It has 2 GB of ram and I know that I am going to up that to at least 4 GB. I am pretty sure that is the max RAM this model supports. If I am off there, please advise accordingly.

I am currently installing Mountain Lion via the Ap Store and once that is done, I will begin the process of making it as empty as possible of extra applications save for Pages ( iWork 2009 ) and one possible work related application. I intend to use this solely as a work machine. I am a professional mediator and provide most of my services pro bono. I share that here to make clear I am looking for the least expensive methods to do what I seek to do with this computer.

I hope that once I am done refreshing - restoring this machine, I will be able to utilize the Mirroring functionality of Mountain Lion and an Apple TV to have what I am typing on the computer to show up on the 47" HDTV in my conference room. This way, my clients can keep their focus on the screen and look for the items being typed and not (hopefully) pay attention to the many areas where they do not agree with the other party in the mediation.

OK, enough of the extras... lol

1. I want to remove all the applications and saved data, pictures, music, anything on the machine without actually wiping the hard drive if possible. If I have to wipe the hard drive via Disk Utility, so be it of course but I want to know how one does that these days without the physical DVD install disk that will be needed to re-install the hard drive once it is all wiped. Am I revealing my lack of awareness with that question? I really just want to have a blank machine as if it came to me from Apple with Mountain Lion installed. Once at that point, I will install iWork 09 and be a happy camper using documents in the cloud via iCloud and the above mentioned Apple TV and my HDTV at the office.

2. Is there any reliable source folks can direct me to for some hardware repair issues? The track pad has a pretty significant crack in the bottom center that has spider webbed out. Track pad works perfectly but I am concerned that will not be the case as time and use continues.

3. The keyboard has a few sticky keys from a beverage spill some three years ago. Again, like the track pad, all keys function fine but the "8" key is a much harder push and the surrounding keys are difficult to push as well. The concern here is for how much longer. Is replacing a few keys an option or does the keyboard come as one unit?

So there your have it. I have some hardware issues that my guess is mostly a labor cost to fix much higher than the parts themselves. I am willing to spend up to $500 to bring this machine up to par but not too much more ( absolute max of $600 ) considering the replacement cost of a new Macbook Pro 13" with a non retina display is about $1,500. If the cost to do the things listed above ends up going over the magic $600 limit, I figure I will live with the machine as is for a month or two without repairs and go pop for the new Macbook Pro and have a new ride out of the box. Trying to be frugal here so please share what wisdom you all have and your exprerince as well. Cheap is not my desire. Frugality and saving resources for those who have little to none is the big picture here.

Let the games and answers begin... LOL

thanks... Pete