Hi again Jonathan, and thank you for the help!
I made a test and it works fine, but the issue is that, as thought, i can't allocate the real memory size to the virtual machine. I have 4GB ram (for example) and i just can allocate 1500 MB.
I wanted this working for testing the HDD's and RAM's of notebooks in an Acer TPM Repair Center and save a proof that they are OK. For HDD's I have a licensed HDD Regenerator usb boot disk for DOS and taking screen captures with Screen Thief running at the same time and hiting a hot key (Alt+Ctrl+T) for the shots. I tried to do the same with Memtest86+, run ST then Memtest but it doesn't work and i don't know why.. maybe because the memory management, well don't really know..
If you remember or find anything just tell me if you don't mind!
Best regards and thank you again,