"Simon" wrote in message
...
I am in the process of building my first two machines at the same time. I
am
planning to build afresh but reuse an two old cases and PSU's. I have
found
that my ATX AOpen AMD motherboards I purcahsed (to go with the AMD 2500
and
2600 processors I got) dont physically fit the cases, and one of the PSU's
doesnt fit into the motherbaord connector either (wrong connector at the
end)
Am I doing something wrong as the cases I am reusing are not that old
(around
late 1999) didnt think building of motherbaords would change so much in
that
time. And do I just need an adapter for the PSU or is it a bin job.

By the way can someone clear this up.....why are some PSU's a different
wattage
to others. I want to run the usual plus two hard drives and a DVD ROM I
wouldnt
need an uprated PSU for this surely.

Newer CPUs and video cards definitely do have higher power requirements.
When you combine that with the fact that many machines use pretty
underpowered power supplies, not really meant for upgrading but for doing
the minimum required in the base configuration as sold, it often is true
you'll need a bigger power supply. Search the web for power supplies and
how to determine power requirements. I'd say you probably, if not surely,
need a new power supply. (the connector alone tells you it won't work.)

Also with themral compuind do you only get
enough appliacation in the syringes for one CPU/Heatsink or will I be able
to
squeeze two out of it.

You can "squeeze" 2 out of it, literally. You don't need much at all, if
it's applied evenly.