I'm creating a layout design for a client's website, but I'm not sure how to tell if I have web licensing. How can I tell? Are the pre-installed fonts web safe?
You might be mixing concepts here.
Historically "web safe" meant that it was a font that was likely to be installed on most everyone's computer.
So, since all Windows machines have Arial, and all Macs have Helvetica, a 'web safe' way to spec a sans serif font might be:
font-family: Helvetica, Arial, Sans-Serif
Spec'ing a font that few people may have, such as Univers, would be risky as not many people would see it on their machine. However, you can always have fallbacks:
font-family: Univers, Helvetica, Arial, Sans-Serif
Today the term "Web font" typically refers to a font file converted into a format that can then be embedded with the page itself--so a user doesn't have to have a version installed on their system.
To use a web font, you do need to use a font that allows for it. This would be outlined in the license.
As for your specific question, can you use a system font as a web font--I don't believe so--but I'm not positive. Typically, a font that comes with your system is already licensed to you for use on that system, and since most system fonts were established prior to the use as embeddable web fonts, odds are that they don't have a web license clause in the license.
pre-installed fonts maybe web safe, i think @da01 covered that well, but they are not free to use on the web. whatever font ms released with windows 8, i forget but you could access it in their mobile dev tools. it was quite popular to use in designs, stubs, etc., but you had to purchase a license to use on the web. or rather, anything other than what the font came with. so (i'm assuming here) using fonts that come with ms word on the web would be most likely illegal