Public computers such as those in offices or school labs have various restrictions imposed on them by the administrator. A limited user account might be disallowed from using USB drives, or burning CDs or making changes to files. The administrator might have also set system wide restrictions. For instance, he or she might have disabled balloon tips, removed My Documents, disabled printers, disabled visual styles and so on.
If you are a limited access user on a public or shared computer and wish to determine exactly what shell restrictions are imposed on the machine, you can do so by using a small program called SHRest. It weights just 15KB in download size and requires no installation or administrator rights to run.
SHRest will show you what restrictions the Admin has on your computer. A green check icon means you are good to go - restriction is not in effect. A red X means the restriction is in effect. The downside of this tool is that the entries are cryptic, usually registry key values with no description of what each item indicates. You have to be familiar with these registry values in order to understand them. Having said that, most of them are pretty easy to guess. Anybody with a fair understanding of Windows shell settings can read them off with ease.
For example, you will find entries like FORCEACTIVEDESKTOPON, NOCONTROLPANEL, NOCUSTOMIZETHISFOLDER, NODRIVES, NOFOLDEROPTION, NOFILEMENU, NOMYCOMPUTERICON. Not rocket science, is it?