No domains, no group policies...you can change permissions on the snap-ins to only allow your username, but you might have to look at programs that whitelist executables to fully prevent users from running things they're not supposed to get into.
If they're not very advanced users you could remove the tools from any menus (are they poking around where they're not supposed to?)
You might also need to have a company policy that outlines what is acceptable and not acceptable use.
Personally I'd look at a whitelisting of executables solution or migrate to active directory where you can get finer grained control over permissions, which may also help with your mapping of shares and such as well.