Leave windows alone and try third part apps (Score 1)

There is a product called Premier Accessibility Suite that could greatly enhance your parents use of the PC. Other than that I suggest you install two disks one for data the other for applications and give them a restore CD and crossloop which works as a excellent remote tool or perhaps sysaid could also be of use as it will log system inventory changes for you. Premier is a commercial program and I do not remember the cost but sysaid and crossloop are open source.