Hi!

I was adding some memory (DDR) to a Compaq 6000T computer
to send to a friend. *This computer is a Celeron 2 GHZ that can
accept up to 2 Gig of RAM. *The minimum speed is PC2100 and
the MB has two slots for memory.

Is this an ASUS board? (read on, you'll see why this might be
interesting...)

Now the interesting part: *I purchased two sticks of low density
PC3200 DDR so that I could put the maximum memory in the
computer before sending it out.
Upon returning to the computer I plugged in the power cord to
the A/C and immediately the computer tried to start without
having pushed the power start button on the computer front.
*It did NOT successfully start, but went into an oscillation of the
power supply starting and stopping every half second or so.

I have an HP Pavilion from about the same timeframe that behaved
precisely the same way. I picked it up off the curb, complete with
monitor keyboard and mouse. It is based on an ASUS board.

The powering on from a dead stop after sevreal hours unplugged
suggests a weak CMOS battery, which is well within the realm of
possibility. This isn't always immediately noticeable, as most ATX
motherboards maintain the memory from the standby power coming out of
the power supply while they're plugged in. The battery is only used
when the system is completely without power.

When the battery goes bad, some boards even lose track of their power
state and come back on as though it is the default state.

My HP system did this, and replacing the CMOS battery (about $3, it's
a CR2032 cell) solved that problem.

But then the cycling started up. I upgraded the memory in much the
same way you did, using PC3200 parts. The system was happy, passed a
memory test and then the next time I went to use it, it would only
cycle repeatedly with a tiny "flub" noise from the power supply. The
cycling indicates a power supply which is going into overload or short
circuit protection, coming out of it when the supply shuts down and
starting the cycle over again.

I cleaned and *firmly* reseated the memory. It solved the problem.

Every now and again, when the weather changes or the computer is moved
(it is not, for obvious reasons, a primary system of mine) I have to
reseat the memory or this problem crops up. My guess is that either
the memory DIMMs were not quite made properly or there is something
slightly strange about the sockets they go into.

William