I've been hired on at a company that provides contract technical support to a number of organizations, and one of the beliefs that I've heard both from users and coworkers is that a reboot is the first solution to try. I want to address what I think about that.
I hate magical solutions.
When a user experiences a problem midday that clears up after a reboot, there's no diagnosis nor documented solution. The problem presented itself and then cleared up magically. There is nothing to suggest that the problem won't return, and intermittent problems irk me like no other.
Case in point: while on-site one day I was called in because the X-ray machine suddenly couldn't send images to the server, and doctors consequently couldn't view patients' X-rays. It turns out that the X-ray machine (running Windows XP, natch) had a duplicate IP address. The X-ray tech told me that the duplicate IP address message had been popping up for months, but always cleared up with a quick reboot.
Long story short, the X-ray machine had to have a static IP address, but someone gave it an address smack dab in the middle of the DHCP server's configured address range. For months the server had been handing out a duplicate IP address and somewhere in the building a user would reboot their computer because they couldn't access the network, solving both the X-ray machine's and their own problem. That particular day, though, one fateful user turned on their computer but had to leave suddenly. Consequently, the computer was left on and hogging that miserable IP address. It was only after much gnashing of teeth that the problem got resolved.
I actually have to get ready for work, so I'll just close by reiterating my earlier statement, but slightly tempered for the benefit of the people who've read this far:
I hate magical solutions (but acknowledge their utility).