No startup - Vostro 1700 - Caps/Scroll Lock LEDs Blink

Dell Vostro 1700 notebook.

Ran very well until I tried to restart it last night. Instead of restart it powered down.

Pressing power button gives the following:

Power light on steady
•HD flashes light on briefly (before it even tries to post/bios) then off
•Num lock LED on steady
•Caps lock & Scroll Lock LEDs blink together for about a minute then the system turns off on its own. (System doesn't respond to pushing or holding the power button during this.)
•Nothing appears on screen, apparently not posting
•Normal sound from internal fan while it's on (big fan not on, but that's normal)
•No system beeps

The main HD is SSD so I wouldn't hear that if it was trying to use it. There is a 2nd physical HD.

I've tried to research this and threads offer a variety of indications and suggestions to fix.

Such as:
»en.community.dell.com/support-fo···826.aspx
»en.community.dell.com/support-fo···229.aspx

Support threads suggest it could be:
• RAM chips/sticks or RAM slots
• CMOS battery
• Motherboard
• Battery, etc.

What I've tried (none of these has changed any symptoms):
• Powering up on battery or AC only
• Reseating both RAM chips, swapping them, booting with one RAM or the other only
• Reseating both HDs
• Opened up whole unit & dusted out, reseating connectors, etc.
• Fn + Power on
• Took out and reconnected CMOS battery

Interesting CMOS battery note: The date stamped on the tape/casing over the CMOS battery is 7 10 12. That's tomorrow's date and it died almost exactly at midnight on 7-9-2012. Odd coincidence? This is the original CMOS battery and the computer is perhaps 5 years old.

I would expect a dying or dead CMOS battery to not cause this drastic a symptom. (Rather, I'd expect it to lose the internal clock date & time, but still boot up) However, I did read in support threads that CMOS might be a cause of this issue. (Question, can I buy a standard CR2032 battery and insert it into that blue casing with wires that the Dell CMOS is inside of?)

Note: I know I'm overdue for a new computer and would be OK with getting one. The reason I want to fix this one is that I don't think new Windows notebooks offer the super high resolution 1920 x 1080 17" displays like this one has anymore.

There was nothing to indicate that something was going wrong with this notebook and there were no drops or spills. It had been dusted out a month or two ago and all was fine. It was in my lap on a sofa at midnight and suddenly wouldn't reboot.