When you see a C: drive and a D: drive on your new Windows PC, you should put most programs/apps on the C: drive. It's the faster drive (especially if it's an SSD), and you will probably be loading and unloading with frequency. The second reason is that Windows often expects to find applications on the same disk as Windows. Reserve your less speed-critical "Data" for the D: drive, which might be a slower, spinning drive.
Some antivirus software can be fairly annoying to uninstall. Rather than going into the list of programs within your PC or Mac and uninstalling from there, the antivirus software can be embedded into your system that it technically remains on your computer even after going through the uninstallation process.
Steven has to install Office on about 30 PCs. Leo says it's called a deployed install. Microsoft has a program called PSExec from SysInterals. He'll have to put the installer on first. Windows IT Pro has an article on how to do it.
SysInternals has tons of great tools that any budding IT guy should have in his quiver.
Leo says it's bizarre. He suggests installing from an original official Microsoft CD. It's likely that the ISO copy he's been using has gone bad, and only going to the original source will fix the issue. The official ISO download links can be found here.
Leo says it's very difficult to move an app to another computer. Not only is it difficult just to move those programs, he's also moving them from 32bit to 64bit which in some cases is just not possible. Windows Vista has the capability to move programs built-in, but Leo doesn't recommend doing this at all. He really should buy new apps or install them from their original disks. Another option is to clone the drive from the old computer, and dual boot Windows XP and Windows 7 on the new computer.