In my experience, if someone "above" you is mad at you for doing something, you will hear about it, rather than have them sneakily prevent you from doing things.
My role as an "IT Professional" is sometimes described as "Last Line" and there is no one, technically speaking, above me. I usually have to report to some management bod with a loose grip of what I actually do for my living. I don't really get mad at people for making my working life difficult, people come with the territory; but they do disappoint or frustrate me at times.
Unless it's downright illegal or opposite my employer's interest, I prefer to view internal exploits the same as external exploits, shutting them down quietly. I prefer to keep one hand on my toolkit, as it were, than waste hours on
wrist slapping disciplinary paperwork. Most people are aware when they are doing something wrong. The day after I cut 1500 people off from Facebook and Twitter, 1st line got only 4 related calls, and 2nd line 3 related enquiries. Nobody went beyond the prepared response, "If you need access to a site we have restricted, for the purpose of your job, please have your manager authorise by filling in the appropriate form."
The aim of every systems administrator is a peaceful life; everything working as it should, procedures being followed, without managers running around like headless chickens constantly repeating, "How long?" Or my favourite, "So what was wrong with it?" [If you had a hope of understanding that, you wouldn't need me to fix it.] Such tranquillity does not come easy. There is enough of what everyone else believes the Internet Pixies do, without looking for human issues.
In fact, having a whole paper trail of "they were warned" is pretty important if you want to actually fire someone (at least in the US.)
There is always the odd one with a superiority complex, who claims entitlement and is determined to take it further. So yes, I keep records to cover my own behind, maintaining an adequate audit trail and justifying my actions in accordance with whatever policy was violated. Whenever possible actions are summary; like finding the night shift have installed a bunch of games on a PC, removing it for re-image and swapping in the oldest, slowest, dog of a PC, festering in the stock cupboard.
When firing is the likely outcome, the first the culprit hears of it is the call into Human Resources. Evidence of illegal activity or gross misconduct is gathered quietly. I haven't done my job properly unless it is overwhelming.
Arduino requires that drivers be installed, in addition to the IDE. It doesn't seem unlikely that a new windows7 install might not include those drivers (it's a more interesting question, why the old install DID have them.)
Windows 7 supports many USB to Serial bridge chips natively, out of the box or through Windows update. Apple distribute their Windows drivers through Boot Camp.
Have you considered ASKING whether they could install Arduino?
Good sysadmins are repressed individuals, with a deep hatred for anyone with down time, who is having fun using "our" computers
