LO and OO calc crash when selecting cells

I have installed LO twice and OO once on Ubuntu 14.04. But they both crash and block everything except the movement of the mouse when selecting cells after months or weeks. I use Calc 10 to 20 times a day…
Both work correctly with XP at school
I tried several remedies descrided in forums but nothing efficient…
How can I install LO on usb key and maybe expect correct use ?
Many thanks in advance

Might be a buggy graphics card device driver, try disabling “Use hardware acceleration” under Tools - Options - LibreOffice - View “Graphics Output”.