Windows 7 - Which security setup to choose for this configuration.

I have given job by my family to build security setup and os for my cousin on old machine.

Machine conf:

Hd= 250 Gb
Motherboard:intel
Processor:Intel pentium 4 2.6Ghz 1.73Ghz
Ram = 2Gb

I am installing xp (as seven will be heavier) on this machine...

I had spare license of Norton 360 and avast internet security
Which one i should install on his machine

He will use machine for browsing downloading music and he often use torrents.

Please suggest.

P.S. I know mse is good option but he dont like mse.

Definitely Avast Internet Security!

Also be sure to install Malwarebytes on your computer for passive scanning.

I would recommend Microsoft Security Essentials
Microsoft Security Essentials - Free Antivirus for Windows

I would avoid installing XP since it is too old, Windows 7 would run fine without any lags.

What ever security setup you use always put some imaging software like paragon or macrium reflect so that even if you get infected somehow you can revert back to an earlier image. Also since you are in xp i might suggest to add a firewall. Try some of the firewall like online armor, comodo or zonealarm and only use that firewall which you find easy to use because if you are not able to configure a firewall properly it wont be protecting you effectively also always run your browser sandboxed with sandboxie for extra protection.

edit: just noticed you said your cousin uses torrent please tell him to stop because its the first place to get infected.

I would recommend using Avast Internet Security with sensitivity for all the protection modules set on high. Also, I would force all his web browsers and P2P program into Avast sandbox. Get Hitman Pro for 2nd opinion and Malwarebytes for weekly scan.