That "CMOS battery Low", "CMOS Memory Size Wrong", "Press F1 to run SETUP, Press F2 to load Default values" message is what you SHOULD get after ANY 'clear CMOS' routine
Sounds like a weak PSU to me... What are the +3.3v, +5.0v, and +12.0v 'A' ratings, from the sticker on the side, (or top), of your PSU?
One thing you might try, to determine whether your PSU is just too weak to get everthing fired up on boot, is to unplug everything that you don't actually NEED in order to boot.
That includes the power leads to all of your case fans and other drives (CD, CDRW, DVD, slave HD and floppy)
(leave the 'ribbon' cables, and your CPU fan, hooked up)
Disconnect any USB devices, and run just one stick of memory.
Basically strip it back to the absolute bare essentials...
It takes more power at boot-up because there is an extra load put on the +12v line (which also supplies your CPU with it's voltage)
This is because your PSU also has to 'spin-up' ALL of your drives, and fans. (and they ALL use that same +12v line as your CPU).
Also, running the system at 100/100 reduces the power needed by the CPU, and that may make it work as well.
Try both methods (whichever seems easier to you), or both together if one doesn't work.
If doing any, or all, of the above eliminates your problem, or at least allows you to boot, then YOU'LL KNOW that it's a PSU issue, and that's a cheap and easy one to solve!
Much cheaper than new memory, mobo, or CPU.
On the PSU, if your +12.0v line is 12A or less, you definitely need a better one to run anything more than a Spitfire and a single HD / CD.
I don't know what kind of budget you are on, but if it's as tight as mine, here's an 'ElCheapo' 400 watt PSU for $11.00...
I've got one on order now... it's got +3.3@28A, +5@30A, +12@25Ahttp://store.mrtechus.com/powmax40pows.html
You shouldn't expect to run a Barton @ 3200+ with that one, but for your set-up it'll do just fine... and it's got 25A on the 12v line.
Here is my new PCChips M848A' ">http://img.photobucket.com/alb...2_T-2-3-3-6-2_M848.jpg v2.1, with a 1700+ @ 2411 MHz, and my trusty old PCChips M810L' ">http://members.lycos.co.uk/mmm...00MHz_Sandra_tests.jpg v7.1A, with a Barton 2500+ @ over 3500+. Some of my fancy cars are on this pag