At all of those urls it says PCMCIA and cardbus. One said something about falling asleep (power saving, acpi, apm, etc.) and then the device not anymore being found.
(oop, I just saw your Slackware url in your sig)--still, I don't want to assume that this post applies to your url in your sig.
(What R U running?) *What* version of Slackware? Which kernel? Which version of KDE? Which version of X Windows? Relevant drivers, say for GUI, etc.? (I hope that PCI-Express isn't too new for Linux). I run Pentium IV socket 478 with Northwood CPU, Intel 865 chip with AGP video -- Linux likes it very well.
When your prob. happens, does the kernel (run level 3 or whatever it's called) go down too?
That is, when it happens, can you, say, on keyboard do (the 3 keys): ctrl-alt F6
and get to (log on to) tty6 (a Linux terminal).
This (terminal) is minus the X Windows -- it's run level 3, *that's* what it's called.
If so, issue the ls command like above. If you get this and if you get a directory listing then your prob likely is limited to KDE and X Windows.
I've had probs with the GUI. But I'm yet to have probs with run level 3 going down on me. And this is since about Slackware 9.0. Now running Slackware 11.0. A Dauntless, unsinkable ship!