switching from root back & forth get blank screens

[gp_centos]

I just reinstalled os6.6 since my system crashed under os7. the problem I am having is when I try to switch from root to user or using log off; in both cases I get blank screens!? and I got to reboot the whole system!
Is there a fix up to it or how it can be fixed?
Thanks.

[ancientnoise]

Hi cp_centos

I just reinstalled os6.6 since my system crashed under os7.

More detail required. What do mean by "crashed"?

the problem I am having is when I try to switch from root to user or using log off; in both cases I get blank screens!? and I got to reboot the whole system!

Which commands are you using or how are you doing this? Is it su - user?

Does the same happen in CTRL+ALT+F2 or via ssh?

[gp_centos]

Just to finish this one, I reinstalled the OS and works fine now. I did try to use switching between the screens but nothing would come up. Since I reinstalled that it is working fine. Thanks.