[xubuntu] Problem with my new installation

hello, i have installed the xubuntu 14.04.04 lts 64bit to my system. First of all is the 64 bit the right choice considering my system specs? Secondly si was wondering if because if i should make any change in the additional drives because i have get a frozen screen (which force me to restart my system) a couple of times. Pleace check my sytem settings above

2 Ubuntu 14.04 trusty 4.2.0-38-generic 64bit (el_GR.UTF-8, XFCE xubuntu), Ubuntu 4.2.0-27-generic
3 Intel Core i5 CPU 660 3.33GHz ‖ RAM 2999 MiB ‖ MSI P55-GD55 (MS-7589) - MSI MS-7589
4 nVidia G92 [GeForce GTS 250] [10de:0615] {nouveau}
5 eth0: Realtek RTL8111/8168/8411 PCI Express Gigabit Etheet Controller [10ec:8168] (rev 03) ⋮ wlan0: 0bda:8171 Realtek RTL8188SU 802.11n WLAN Adapter