[Ham-Computers] Heat Related?

[KD7JYK]

I talked to my friend about her computer shutting down, she opened it up and
found a lot of dust inside, especially around the processor fan, so her her
problems may have very well been heat related, other tests yielded no
results.

Another question from her today:

"I've been selecting and deleting emails, and my computer started acting
nuts again - as in when I have selected a bunch of records it suddenly makes
copies of them all so now I have twice as many to delete.  Did you ever find
out why it does that?"

Any ideas?  I have never experienced anything like this.

Kurt