No Display when CMOS battery is plugged in

Hi,
Below is the system configuration.
Mother Board - Asrock G31MS (4 Years Old, Bios Updated to latest version)
CPU - Pentium Dual-Core E2200 (5 Years Old and Never Overclocked)
Monitor - LG 42" Plazma TV
HDD Internal - Western Digital 320 GB
HDD External - Transcend StoreJet 500 Gb
RAM - 2 Gb Kingston (2 years old)
Display - On Board (No Graphics Card)
USB TV Tuner - Avertv Volar Go A833
Amkette - USB Hub with external power supply
Wireless Keyboard and Mouse - Logitech
OS - Windows 7 Ultimate 32 Bit.

Around 10 days back i observed that the CMOS battery was drained and it required a replacement as on every boot system prompted for loading default bios settings. I had removed the old battery without putting a new CMOS battery for 7 days. Now on the 7th day of the system running without any CMOS battery, I observed that there was no display but cpu fan and all leds were blinking. As i do not have Chassis buzzer I did not hear any beep. There was no need to clear CMOS settings for display as there was no battery inserted and on every boot i used to press F1 to load defaults and once the system is booted up, I used to change time from OS (Windows 7 Ultimate) My initial doubt was CMOS battery hence immediately i purchased 2 brand new CMOS batteries and replaced it.

This did not help. Hence I removed, CPU, RAM and HDD. Cleaned the RAM, CPU FAN and put everything back along with new CMOS battery. I was quite sure that this will do the trick. However it did not and results were same i.e. no display CPU fan and all LED lights were on.

As a next step I removed the RAM plugged it in my neighbor's system and performed windows memory test (mdsched.exe). Test was successful without any error.

Further (as read in one of the threads) I cleared the CMOS settings (by removing the battery for around one hour and plugging out all power supplies.) Post which i put the CMOS battery back and powered on the system, still there was no display but I kept the system running for 15 minutes. After 15 minutes I powered off the system and powered it on. THIS TIME I GOT THE DISPLAY and system was functioning absolutely smooth without any problems or errors. I played full HD Videos and my TV was also running for around 12 to 13 hours (on USB tv tuner avermedia volar go), there was absolutely no issue.

There was no problem faced regarding the display till the time I shut down the system. Before shutting down I had restarted the system for around 4 times and after every restart there was no problem in display. But as soon as i shut down the system and then powered it on, the display went off. Again I did the same process, clearing the CMOS (by removing the battery for an hour as I do not have CMOS jumper caps), power on the system with CMOS battery plugged in, wait for 15 minutes, power off the system, power on the system (no display but cpu fan running and all leds are on) and then there is display.

As the third step read in one of the threads I upgraded my bios to the latest version but that also did not help.

Further I read on one of the threads in forum that wireless keyboard and mouse may cause the problem hence i switched to my spare USB keyboard and mouse (Wired) that too did not help.

Kindly suggest how to get read of this frustrating problem.

Aditya Shah.