openSUSE 12.2 has become unstable

My system has become unstable:

It sometimes just quits without any warning and aborts suddenly, as if I had
disconnected the power. It seems if this happens I am usually doing something
that takes time, such as, for instance, backing up to a memory stick. In this
context, don't know if it matters, I have 3GB RAM and 1TB storage available just
for my one Linux OS, only a very small portion of the 1TB is used.

Another, more unusual, occurrence is that the system freezes completely which
can only be undone by my pulling the plug.

In all these situations, I restart normally or with Advanced Options, and
everything is fine again.

I am trying to decide how to fix this and restore my OS to its former glory,
preferably while keeping all my settings, apps, drivers, etc. Perhaps, even
with keeping my personal data though I can of course bring those in from backup.

How? I need the benefit of your greater experience and wisdom. Which:

Use some special repair setting when booting?

Reinstall 12.2?

Upgrade to a more recent version of openSUSE?

Newly install the most recent version in addition to and separate from 12.2?

If there wasn't an issue with my settings, apps and such, I would of course
simply install openSUSE's latest version.

Thank you and have a nice day,
pe1800