Repairing volume on 2009 MacBook Pro

[dwighty pork]

Hi - am new on here and have a particular problem.
I bought a 13" MacBookPro in 2009 - it came with Mac OS 10.5.7 which I believe is Leopard, running on Intel Core Duo.
The following year Snow Leopard came OUT and being a bit naive at the time, I allowed myself to be persuaded by a friend I could save money by downloading a torrent version of the new O.S. which he did, copied to disk and was able to get it running...
Now, on using Maintenance and double-checking with Onyx, I have problems with 'volume needs repairing - load from original install disk'.
Can I do this from the original MacBook Pro Leopard install disk which I have ?
I am no longer in contact with this ex-friend and do not have the disk copy by which he put Snow Leopard on my machine - curse the day...
Will my original Leopard disk work - or will I need to do something more radical ?
I have recently bought a proper Apple Retail Snow Leopard 10.6.3 disk and wondered if I could use this to get my machine running normally ?
Should I back everything up and go for a clean install or just try repairing disk permissions ?

Any help and advice gratefully received !

 

[GGJstudios]

I have recently bought a proper Apple Retail Snow Leopard 10.6.3 disk and wondered if I could use this to get my machine running normally ?
Should I back everything up and go for a clean install

Yes, do a clean install using the disk you bought. It's a very bad idea to install any torrented (stolen) software, as you could be installing malware along with it.