Backtrack 5 (64 or 32 bit) will not go into Xwindows after install to the harddisk. I can boot from the Live CD/DVD and all works fine, If I remember right the 32 bit version worked in a VMware virtual machine unders 64 Bit Windows 7. When installed I login text mode and type startx <enter> and I end up with the CAPS LOCK light flashing and the system hanging with a grey/black screen. I tried fix_splash and no help. I have used Ubuntu 10.04 thru 11.10 in 64 bit mode as well as Blackbuntu 0.3 in 64 bit mode with no issues.
Backtrack 5 R1 fixed the issues I was having with BT 5.0. I didn't start with R1 because I initially thought it was a "release candidate" and not a full release.