My Acer ( Windows Vista Home Basic)laptop has suddenly started to have a closedown problem.
Close downs seem normal then... Every third or fourth closedown a blue screen appears with Message and
STOP 0X0000007E (0XC0000005,0X81C969BA,0XAE083C30,0XAE08392C).
I then have to do a forced closedown and on the next startup the computer boots normally.
Last Known Good Config and also System Restore failed.

Sounds like a memory issue.
RAM could be going bad on you.

Are you running 1 or 2 banks ?

2038 Megabytes Usable Installed Memory

Slot 'DIMM0' has 1024 MB (serial number 0xCE382126)
Slot 'DIMM2' has 1024 MB (serial number 0x74352126)

I appreciate your quick response to my first mail Curlyben.You may be right about memory.
My second mail was a very hurried copy taken from Belarc advisor.
Does that indicate that there are 2 banks or can I confirm this elsewhere?

Yep, shows you have 2 banks.
Try removing 1 and rebooting, if this works then it's confirmed as good, otherwise try it with the other one.

Hope that makes sense.

Apologies for taking so long to respond. I must explain that it was impossible for me to remove the screws on the back cover with a small screwdriver because they had been put on so tightly at the factory. I had to go a technician in a neighbouring town and explain.
In brief,his conclusion was that it was, in all probability, a memory problem , not the Memory Hardware (he did not bother to remove the banks) but because there were too many downloaded programmes, especially security, cleaning and maintenace programmes which are not really necessary and are in effect overkill and also possibly conflicting on occasion.
I have to admit that I enjoy grabbing special offers and trying new programmes and then having difficulty choosing which to reject and also I have been guilty of thinking one cannot have too much security.
However after clearing out my 'downloads' file and uninstalling three or four programmes (which I can reinstall if ever I decide I wish to use them), I am pleased to say that now I do not have the Blue Screen 'STOP' problem .
My thanks again for your help Curlyben.