At least you did not pay to find out-- I am sorry, man.
I really thought that this would fix it....GRRRR.
Under-powered usually does cause a lot of weird stuff-- I'll be back-- & will ask for 2nd opinions from others-- this really narrows it-- but we're not quittin' yet.

Stubborn is my middle name...

OK mate, I really appreciate the help.....

I'll start doing some research on replacement mobos.

What brands are reliable and good quality? Asus, proper Gigabyte?

Thanks again.....

I run ASUS-- mine is 5 years old-- never an issue.Consistently high ratings-- I have a P4P800 Deluxe. Runs 24-7 most days. I don't believe I have ever read a bad review of an ASUS board. The only thing I ever did was dust it-- and replaced the CMOS-battery once.

You have Processor/RAM... I'll see what I can find too.

Gigabyte has a following...but I've seen some inconsistency-- plus this was originally a Gig board.
Pine
A-open
ABit

Personally it's ASUS for me but Pine or Abit would do fine too.

AnandTech: Socket 754 Roundup, Part 3: Asus, Soltek & DFI

want good appraisals of gear...? Anandtech is a great place

Sorry to hear the PSU didn't work for you Kezza, but I do fully agree with bills, ASUS are definately my favourite, and ABIT would probably be my second.

That's an older Fortron ...not a bad unit for what you run. I've seen them mentioned in overclocker forums as being decent.

Hey Mad... any suggestions on where to shop 'over there' ?

I'm spoiled in the US-- there are too many good ones here.
Newegg for starters.

Have no clue there...
and you know a bad vendor can be a nightmare.