Validation of OS or reformatting

Hi my name is Paul and I recently purchased a used Macbook Pro off of eBay and I need to see what if anything I can do to confirm that the OS and other items loaded on the unit are OK and not infected or any weird things like that. I don't want to find out that the person installed some sniffer software and will be able to get into the unit once I receive it. Should I trust someone elses system in that there isn't anything weird loaded on it? I say no.

I'm a PC person so please keep that in mind if what I ask isn't in the correct terms for the MAC world.

I was thinking of just reformatting the drive and re loading the OS but I won't have any disc for the OS. In the PC world I could make a set of start up discs that would allow me to re load the OS. Is there something like this in the MAC world?

Thanks for your help and be gentle with your responses, I'm trying to convert.

Caution is good always, but you are probably fine. Reformat and fresh OS install is outstanding idea for second hand Mac.

Post your OS (10.5 10.6 etc) and Mac specs and we will give detailed advice.

I have not received the unit as of yet but here is the info from the seller.

Model ID MacBookPro4,1
Model Number A1260
MPN MB133LL/A
Mac OS X10.7 Lion and has Office 2011 and iLIfe 2011 installed.

Best bet is to purchase Lion on USB direct from Apple ($69 USD) with that you can reformat and reinstall the OS.

As it is you really don't have an OS as the one on it is linked to the original owners account.

Yes that sounds like the best thing to do.

Thanks Razormac.