Unable to get higher resolution 800x600 & monitor doesn't detected

I am not able to get higher resolution in RHEL 6 (santigo) i.e. 800x600. apart from this monitor is also not detected.

below I have provided necessary details.

[root]#cat /etc/release
[root]#RHEL server release 6.0 (Santiago)

[root]#uname –mrs
[root]#Linux 2.6.32-72.el6.i686

Note- RHEL 6.0 doesn't create any Xorg.conf file. So, there is no such file /X11/Xorg.conf file at this location.

My main concern is to get other resolution which I have mention below in GUI mode.

Modes "1280x1024" "1280x800" "1024x768" "1024x800" "800x600" "640x480"

further additional information.

[root@localhost Desktop]# lspci -vnn | grep VGA -A 12
00:02.0 VGA compatible controller [0300]: Intel Corporation Device [8086:0166] (rev 09) (prog-if 00 [VGA controller])
Subsystem: Intel Corporation Device [8086:2111]
Flags: bus master, fast devsel, latency 0, IRQ 11
Memory at f7800000 (64-bit, non-prefetchable) [size=4M]
Memory at e0000000 (64-bit, prefetchable) [size=256M]
I/O ports at f000 [size=64]
Expansion ROM at [disabled]
Capabilities: [90] MSI: Enable- Count=1/1 Maskable- 64bit-
Capabilities: [d0] Power Management version 2
Capabilities: [a4] PCI Advanced Features
00:14.0 USB Controller [0c03]: Intel Corporation Device [8086:1e31] (rev 04) (prog-if 30)
Subsystem: Intel Corporation Device [8086:1e31]

root@localhost Desktop]# xrandr
Screen 0: minimum 640 x 480, current 800 x 600, maximum 800 x 600
default connected 800x600+0+0 0mm x 0mm
800x600 61.0*
640x480 60.0