For Mac users, it is trivial to download the Java JRE and plugin, and simple as pie to enable or disable Java, I've done this in about 30 seconds on multiple Macs....unlike the piece of sh*t implementation we deal with on Win 7 enterprise at the office where our payroll partner is about 3 generations behind on their Java config, so our systems are forced to use an older version for 'compatibility' reasons.....what a joke. There is a bunch of tribal wisdom in this thread that is just dark humor, if you catch my drift.
On your home Windows7 machine it's also trivial to download the Java JRE and plugin and as simple as pie to enable or disable Java.
What you're talking about isn't a problem with Windows7, but rather a problem with your payroll partner.
This discussion is not whether Java is easy to use, install and upgrade, but rather whether it is acceptable to remotely kill your payroll partner without asking whether they need that Java first.