General flakiness with X61T, Win XP Tablet SP2

[gpvillamil]

I've had an X61 Tablet now for several months. It's worked out mostly pretty well. However, in the past month, it's been getting generally "flaky" - I want to know if there is a software fix, or if it sounds like a hardware problem.

* Sometimes (about once every two weeks) the network connection will just stop. Browsers will not connect, but with no error message. Just a blank page.
* When that happens, I can usually fix things by rebooting. But when I do, I get a blue screen, saying something about rdbss.sys could not cancel pending operations.
* The Intel Gigabit Ethernet driver in the device manager shows a yellow exclamation mark (this is recent). Uninstalling and reinstalling the device in the device manager does not fix this.
* Sometimes, when shutting down, I get an error message along the lines of "memory at location xxx could not be 'read'". This message keeps popping up, until eventually the system shuts down.

What's going on? Could this be malware? Software? Bad memory? Bad system board?

The problems are fairly sporadic, but I worry that they could hit when I'm doing something important.