I just purchased Sonar Platinum, and I'm trying to open an old X2 project that used Pentagon I (I guess Pentagon I is no longer included with Sonar).  It's a new computer and I don't want to install an old version of Sonar just for this one thing.  
 
So I found the page for it on Cakewalk's site (), but still can't find a link that would allow me to purchase it again.  It seems like they would take down the listing if there isn't a way, though?  Anyone?

Pentagon has not been sold separately in years.
To get Pentagon installed, run the X2 installer and choose the advanced install option and only install the plug-in.

Ugh...my new computer doesn't even have a disk drive...I guess I really have to download 5.4 gigs of Sonar X2 just to select this one option.

IIRC all of the Sonar X were downloadable installs.  Best to make a local archive of your installers anyway.

Okay, for anyone needing to do this in the future:

• You need to redownload 02_Sonar_X2_Producer.part1.exe through 02_Sonar_X2_Producer.part4.exe.  After runing them, the installer opened gave me the "Advanced" option to only install Paragon.  Interestingly it still reported needed 1 gigabyte of install space even if I chose nothing; not sure what that means.
• I had no luck finding the default Paragon presets.
• You need to set the Sonar Platinum shortcut to Run as Administrator (this means browsing to the shortcut  location, right clicking, choosing properties, compatibility, and finding Run as Administrator in there.
• Cakewalk Amp Sim was missing too so I installed that.
• I also installed Dreamstation Dxi because I was missing it, but in retrospect, I don't think there is a way to use this in Platinum.
• I'm apparently missing Cakewalk FXFlange, Cakewalk FxReverb, Cakewalk FxEq, etc. that I didn't even see an option to install...so maybe those predate X2?

 
Overall it's pretty frustrating that this program isn't backwards compatible with the 2012 version, and it makes me wonder if songs I write now will no longer work in a few years (especially since I will still be having to make edits of the same projects in that amount of time).  I haven't really noticed this ever happening for Photoshop, 3D software, video software, etc, so is it just a DAW thing?  Or a Cakewalk thing?

Many of the very old DX plug-ins and synths were not ported to 64bit. Those that were still bundled with X2 do not get installed by default when installing 64bit X2 because the plug-ins will only run in 32bit SONAR.
 
If you plan on opening a lot of old projects relying on DX plug-ins that were not ported to 64bit, consider installing 32bit Platinum. It is possible to have both 32 and 64bit Platinum installed on the same machine. Having access to 32bit Platinum may help during the transition to 64bit. Old projects containing the DX versions of Rapture or DPro present some special challenges.
 
If you feel comfortable with regedit, here are the instructions to modify the registry so Pentagon loads without running SONAR as administrator http://forum.cakewalk.com/FindPost/3599131

scook
If you plan on opening a lot of old projects relying on DX plug-ins that were not ported to 64bit, consider installing 32bit Platinum. It is possible to have both 32 and 64bit Platinum installed on the same machine. Having access to 32bit Platinum may help during the transition to 64bit. Old projects containing the DX versions of Rapture or DPro present some special challenges.

Actually, how would I do this?  I installed the 64 bit version using the Cakewalk Command Center...I don't honestly recall if it gave me an option to do 32-bit, but now that it's installed, I don't see a way to get *back* to such a choice (though if I right-click I can uninstall).

By default the Command Center installs the version appropriate for your OS. Here are the steps to get the 32bit installed too. Keep in mind, just like the initial install, updates will require running the installers twice.
 

• Open the Command Center
• Click the gear in the upper right to open the Command Center Settings
• Check the "Verbose Install" option
• Click Save to return to the main page
• Re-run the installers. This time you will get the 32/64bit install option. Select the 32bit option to force the 32bit install.

In my case I put the 32-bit version of X3 back on my computer, with the 64-bit version of Platinum.  I keep my 32bit stuff partitioned in the X3 world and open up old projects over there.  The same could be done with X2 or Platinum as well...

abacab
In my case I put the 32-bit version of X3 back on my computer, with the 64-bit version of Platinum.  I keep my 32bit stuff partitioned in the X3 world and open up old projects over there.  The same could be done with X2 or Platinum as well...

Yeah, I may do just that.  While I get the option to install the individual plugins as 32 or 64 bit in Command Center, for Sonar Platinum itself I just get "Install All" (which installs the remaining plugins I didn't install at first) or "Launch".  I probably need to uninstall it to get back to the point where it gives me the  option of 32 or 64-bit.  Or else let it "Install All" and then maybe it'll give me the "reinstall" option.  Anyway since it seems like Platinum just flat out doesn't have a lot of the old stuff I'd want anyway it makes some sense to install X2 again.