Convertxto dvd problem (again)

FREEZE PROBLEM YET AGAIN!!!

Had this problem before (see earlier thread)

The program can convert smaller video files (i have been able to convert / burn tv episodes etc.)- so i know the program can work and that it's not a codec issue etc. - but anything over 45mins causes my whole pc (which i've virus/malware/adware/spyware checked, defragged, uninstalled all unneeded progs, reinstalled windows, tried about a dozen different versions of convertx (as well as many other programs), made sure cpu isn't overheating (my pc has never been above the 37degree mark etc. etc.) to freeze.

In terms of the convertx logs, they read like a normal + successfully working conversion (they just stop at around the 40 odd minute mark - so no need to waste space here).

Any more ideas?????

Your help would be very, very, very much apprieciated.