I tend to agree with Logos on this one.
An older system may not be able to handle some
of the newer developments in program technology.
Having said that, I did come bearing a link you
might be interested in. I have used it in the past
for older systems....
http://www.oldversion.com/ You may be able to find some older versions that will work better
for you. Remember, older versions may no longer be supported,
so no updates will be possible. The first thing I have always
done in this case is turn off auto update feature in whatever
software that I chose to use. This is just a suggestion,
and in no way should be taken as advice from !avast, or anyone who works
for them...which I do not.