Without using the Motion Titler at all, do you have the same trouble with Studio 14? Is that the #1 wreck-all jinx?
Do you also have Studio 12.1? Does it yield a better result?
The money spent on S14 is gone. If you get it back, peace be upon you. It may take Pinnacle weeks or months to issue a corrective patch. Since there is no "known issues" posting in the Knowledge Base, I'd not wager it will come soon or be comprehensive.
Meanwhile, the money you lose by persistent problems is far greater than the monetary investment in the software.
Your system and needs may be ample enough to support a more advanced software with stronger support. Consider the Adobe, Edius, or Sony suites, or perhaps even Avid's AMC,
I'm not sure, though, that any NLE works best if the PC is simultaneously used for other applications.