My question is guys, I have a really old computer, it still runs with no problems, with Platinum installed...
I am very poor,  at this time can't afford much...
I have a Asus M4A785-M motherboard
AMD 11x4 620 2.60 gig processor
With 4 gigs of DDR 2 ram...
I know some of you guys are getting a good chuckle right about now, but this
machine has served me very well over the yrs...
Should I add more ram, or should I just bite the bullet and get a total upgrade...
I think I already know the answer, but I would really like to get some feedback from you computer guys...
Please help the needy!! lol..

What OS do you have now?  XP? Vista? Win 7?
If you have a 64 bit OS and Sonar is running OK and you can do what you need to do, I would suggest upgrading the RAM to 8 GB.  However, if you have a 32 bit OS upgrading past 4GB will do you no good as a 32 bit OS can't address even the full 4GB. 
 
Bottom line a new system would be great, if your recording hardware has Win 10 drivers, but if everything is still working OK, I would leave it as.  Eventually you will want to upgrade so start salting away $$ for the day you do need the new system.

The M4A785-M  holds a maximum ram of 16 Gb.  I say buy the max ram for now and save the money for a new rig.  The ram will help you with the memory to run Sonar Platinum properly.
 
Get 4 x DIMM, Max. 16 GB, DDR2 1200(O.C.)/1066*/800/667 ECC,Non-ECC,Un-buffered Memory
 
If you are using Windows 7 or Windows 8 it will be OK.
 
 
Sonar Platinum Minimum requirements for Installation. (Not for operating successfully)
OS: Windows 7, 8/8.1 or 10 (32- or 64-bit)Processor: 2.6GHz Intel or AMD multi-core processor (at least Intel i5 or AMD A10 APU recommended)Memory: 4GB.Hard Drive: 5GB for minimal install (20GB recommended)Monitor Resolution: 1280x800 (1920 x 1080 recommended) 
 
 
 

I am running windows 10 64 bit guys, I'm thinking maybe ad more ram, and try to squeeze another yr out of it...
Thanks for the suggestions....

I agree with the advice to max out the RAM at 16GB.
It won't net any additional processing power, but that would allow you to run virtual-instruments more comfortably.
I'd halt there... and save up for a full upgrade.
 

More ram will help.  So will freezing any tracks with effects.  That is how we did it in the Neolithic days 10-15 years ago when adding a simple reverb would crash a mix.

You could try to overclock CPU, at least it's free and you can expand paging file size :) 

As you can see in my signature, I am "conservative". My 9 years old primary development (at work) notebook has died 3 weeks ago... My boss has promised me to throw it from my window (4th floor) in case I do not replace it till the end of this year, so that has happened
But at home I am the boss for myself.
 
The question is what you do not like in your current setup? If Synthes you need do not fit into RAW, you are forced to get more. But in case you see the ram is not an issue at the moment but everything is "slow", check the hard disk speed. Unlike DDR2 (which is relatively expensive pro Gb compare to the modern), SSD disk you can reuse in your next system.

+1 to adding a SSD drive to perk things up. 
I have a couple of old Laptops with similar specs, And because at a certain point buying RAM for old machines becomes to expensive I leave them at 8 GB. But adding an SSD drive really sped things up. One is even running XP. 
I do use the one W7 64 bit machine mostly for audio recording and RAM has not been an issue.
Another W7 Laptop with 8 GB RAM I use at work I do 100% midi and have at least 4 soft synth going..no problems there either. 
You can find 240 GB SSD drives for well under $100 now. 

Certainly more ram will help. First quarter of next year, AMD is supposed to release new processors and introduce the AM4 socket. Initial reports look promising.