Just read about swelling of the capacitors (caps in trade) think best
bet is a new mobo becoz when caps swell you can bet gas as been
generated. good capacitor's will have pure capacitance, but as it
ages it dries out and becomes less effective as a capacitor due to
the increase in 'series resistance' as this ESR rises, the capacitor
looses its abilitiy to handle the HF pulses and generates heat which
in turn generates gas thus the expansion, modern ones usually have
vent's in to stop explosion and are rated at 105 degree C (some new
ones are rated at 125 degree C) - not that they reach these
temperatures, just the maximum environment they can cope with.

Low ESR caps handles the high frequency pulses better than normal
types.

I'll try to explain,
For example a normal transformer power supply would rectify and
smooth at 50/60Hz and use normal capacitors (standard 85 degree C
types) and indeed all components would need to be large.

A switch mode power supply normally rectifies at about 18KHz Low ESR
caps would smooth the HF ripples better than standard ones.

A switch-mode supply is a lot more efficient and indeed a lot less
smaller becoz they don't use a whopping big transformer, imagine the
size of a 50/60Hz transformer and the size of components to supply
your 3.3V @ 20 amps or so for your cpu and RAMs (amongs other
voltages required).

The reason for this comparison is becoz computers runs on HF pulses

I very much doubt you will improve matters only by a mobo change, if
you retain your HDD you SHOULD be able to remove old drivers after a
mobo change and install new ones.

I would imagine the problem you are having would get worse over time
due to the caps, also I did not mention (which could be even more
serious) when capacitors expand, they leak electrolyte and if this
gets onto the copper tracks it could either become 'leaky' ie act as
resistances or even corrode the tracks - so take a close look around
the base of the caps, sometimes you can smell the stuff

Sorry for not reading the thread properly - my fault maybe third time
lucky.