Computer freezes/won't shut down or start

I am having a weird problem!

I have a Sony PCV-RS310, its less then 2 years old. Here's whats
happening:

Usually happens when I'm watching video or listening to MP3s, but
occasionally has happened when its just sitting doing nothing. It will
just freeze and sound like its skipping "Hello how are you
today-today-today-today-today-etc". The computer is non-responsive when
I try to Alt-Ctrl-Del, sometimes I can move the mouse but it's REALLY
choppy (and I can still turn on and off num lock on the keyboard) and
eventually totally freezes, but can still see the picture and hear the
looping sound. The power button will not shut down the computer at this
point, even if I hold it in. So I end up unplugging the computer. Once
I plug the computer back in, the power button does not work. Sometimes
I jiggle some of the cords plugged into the hard drive, etc and then it
will turn on (could be my imagination). Sometimes that doesnt work and
I just wait a few minutes, then it works. Ocassionaly, I have had
success unlocking the computer even while it's running by jiggling the
hard drive cables. However, today it does not turn on at all! I also
want to mention my computer also sometimes loses time.

History:

This has been happening occasionally for about a year. Last night it
happened 6 times and then died! It also died a year ago and I took it
into Sony to fix it and they were horrible to work with. They
re-formatted my hard drives and said "here ya go!" and thought nothing
was wrong. Now a year later I'm back to where I was before, only this
time, I'm not under warranty!!

I have tried:

New hard drives
New hard drive cables

Any ideas what this could be? Before I spend a fortune on getting
someone to look at it...

Thanks

 

This could be a RAM issue. Remove the chips, clean the underside with a
pencil eraser, swap the positions in the slots(if you have more than one)and
if still a problem run memtest86(available at memtest86.com)which is
downloaded onto a floppy or burned onto a CD, then run for several
hours(make sure you then change the boot sequence to whatever device will
run it).

 

after a year startup programs could be reinstalled, check to see what you
have running in the background (ctrl-alt-del) from your desktop. You might
be suprised at how much is actually there. You also may need more ram to
watch video on your system with other programs running