kubuntu 12.04 performance deterioration

[joe at actionline.com]

After installing the latest version of kubuntu on my thinkpad,
it started out working fairly well, but performance gradually
deteriorated horribly.  I've tried every "fix" I could find on
the net, but every time I get something fixed, something else
goes haywire.  Many things to like about kubuntu (i.e. suspend
actually works) ... but, every time I logout/in or reboot, it
something goes wrong.

Firefox was working fine, but after closing the lid (to suspend)
and later opening the lid again, Firefox will not start at all.
Both Konqueror and rekonq also are flaky and they also will
hardly work at all.  Very, very slow, jerky, and locking up.

What can I do to get this fixed and stablized?

PS: Like lots of other people whose notes I have seen, I "HATE"
the cashew and all that stupid "activities" business, but as far
as I know, KDE is the only desktop interface that allows multiple
virtual desktops with different backgrounds on each one.

Or is there some other option?