LockUp

LockUp is a tiny software application with a very simple purpose in mind: to restrict the access of other users from launching programs. It lets you create a whitelist or blacklist and doesn't require installation.

No setup necessary

Since this is a portable product, you can drop the executable file anywhere on the disk and just click it to run the tool. Programs can also be blocked by saving LockUp to a USB flash drive to directly run it on any machine without any installers.
An important aspect worth keeping in mind is that it doesn't create new entries in the Windows registry, so it doesn't increase the risk of OS stability issues.

Create a whitelist or blacklist

Packed up in an easy-to-use interface which consists of a normal window with a neatly organized structure, you can block access to programs either by creating a list with all apps to keep an eye out for, or by blocking all installed applications apart from the ones you mention in the list (LockUp is added there by default).
All changes are applicable with one click. Once you or another user attempts to launch a no-access program, the computer shows a message dialog. In order to revert these modifications, all you have to do is open LockUp and clear the list. Plus, it's possible to remove any selected entry from the list without eliminating everything.

Evaluation and conclusion

Everything worked well in our tests, without hanging or crashing. As expected, the app had minimal impact on PC performance, since it required low CPU and RAM to function normally. Thanks to its intuitive interface and options, LockUp can be handled by all types of users who want to block access to specific programs without having to worry about complicated techniques to do so.