Hello,
I just got a new computer (section B) because XP has become obsolete and I need help on choosing a Sonar software and sound card for that new PC.
 
A. Main Computer – using more for rough work thus becoming a secondary computer
I have just removed Windows XP Home Edition from my main computer:
1) 2 GB RAM (Max)
2) Pentium 4 CPU 3.40 GHz 3.39 GHz (Max)
3) 80 GB HD (Max)
4) That has the Sonar 5.2 Producer edition, actually Version 5.0 with 2 updates)
5) That has Creative Soundblaster Audigy 2 ZS (WDM)
 
What I now did is:
1) Install Windows 7 Pro Service Pack 1 32-bit
2) Install the Sonar 5.2 Producer edition, actually Version 5.0 with 2 updates
3) Install Creative Soundblaster Audigy 2 ZS (WDM)
 
This is to create a secondary computer
 
 
B. 2^nd Computer – becoming main computer:
1) Windows 7 Pro Service Pack 1 64-bit
2) 4 GB RAM and about to maxed to 8 GB
3) 300 GB HD
4) Duo Core E8400 @3.00 GHz 2.99 GHz and about to be maxed to Quad
5) Looks like I may get the latest version Sonar Platinum. Would this be correct as to replace that Sonar 5.2 Producers Edition on other computer and will use this on this computer?
6) What do you suggest for a soundcard at roughly the same price as the Sonar Platinum? Pls give suggestions of anything in quality at about same price of Sonar Patinum.
 
This is to create the primary computer
 
 
Overview
The reason why I need help in catching up is that for the A. computer during that XP era when I had 5.0 Sonar Producers (upgraded to 5.2) and that Sound Blaster Card Audigy 2 ZS this combi packed quite a punch and I was up to date with trends.

But now for B. computer I was wondering if I should spend top dollar on the latest Sonar Platinum and some quality card
OR go cheap and maybe go on eBay and get say a Sonar 8, ?Sonar X2 (whatever works with Win 7 and supports 64-bit) and also find the same Sound Blaster Card Audigy 2 ZS or comparable quality?
 
Thanks.

You should really purchase a sound card made for music production if you plan to make music with the computer.

You don't really have to spend too much money to get a good one though,if you don't want to .

I'd recommend a Focusrite in the Scarlet-family of you want to go cheep. There are different options depending on your i/o-needs.

If you have the money though I'd STRONGLY recommend an RME-card. Have used these since the mid 90s and their gear is just top notch regarding absolutely everything. Rock solid drivers (they also never stop updating drivers for older cards just to make you buy the latest one) , great ad/da, quality build.. Can't praise them enough.

Ditto on the Focusrite Scarlett Range

A sound card would be a mistake. It sounds like you have old motherboards that probably have PCI slots which are really obsolete now. You want an inexpensive USB audio interface that will serve you well on any new computer as well as the antiques, and the Focusrite Scarlett series are a good choice. You might be able to find an old PCI sound card used, but you might have trouble finding a driver that will work.
 
Without knowing how you intend to use the software, recommendations are guesswork.
You probably will not be able to find a legitimately licensed copy of  SONAR 8 if you are living in a part of the world where the law recognizes the EULA as binding. Cakewalk licenses are non-transferrable, so unless someone has an unopened (or never registered) full (not upgrade) version of the software you cannot legally use it. Whether you need SONAR Platinum or not depends on whether your intended use will benefit from the bundled features. 

If you have a legitimate copy of Sonar Producer the upgrade to Platinum is a no-brainer.....well you should have made this decision and acted about a month ago to get lifetime updates, but it is still the proper choice to make.
 
The other version of Sonar you mentioned you will not be able to find a legitimate version on Ebay.  
 
Agree with others, don't even consider getting anything made by Soundblaster, just consumer grade junk for music production.  
 
 

If you are looking to save money, consider spending more on your sound card and less on your DAW.  Check the specs for the new Music Creator before shelling out for Platinum.  If you don't need unlimited tracks and unlimited synths you can get a lot better result spending on your interface.
 
I meant Home Studio (if you upgrade to Windows 10), but Music Creator is pretty darned good.
also: Ditto on the Focusrite Scarlett Range

The least expensive DAW package in IMHO
Sonar Home Studio $50     http://www.cakewalk.com/Products/SONAR-Home-Studio
Scarlett Solo $ 100        https://www.sweetwater.com/store/detail/ScarlettSoloG2
 
But the one I would recommend: 
 
Tascam us 2x 2  $150   https://www.sweetwater.com/store/detail/US2X2
 
And as far as Sonar goes Home Studio will blow away Sonar 5 by miles. It's core functions are identical to Platinum. 
Then its a matter of deciding how many plug ins,VST's  and enhanced editing features your after and how much your willing to pay to get them.
. 
 http://www.cakewalk.com/Products/SONAR/Versions#start