Disclaimer: Please note that this article is for information purposes only. Please use this method only for testing purposes. If you want to use full capabilities of software after the trial period, please purchase ‘em. 
UPDATE (Want to use your favourite applications without Administrator rights… read my latest blog post Web Hosted Applications to find out more ways to run your applications without admin privileges)
(Want to Install/Use your favorite applications but do not have administrator privileges to do that… Then please read http://abtevrythng.blogspot.com/2009/08/using-installing-applications-without.html for a workaround)
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Many times we use software that are bound to be used only for limited period, trial versions are available which let users use fully functional software on trial basis for a limited period of time (like 15 days trial) OR in some cases trial versions come with limited functionality. This method can be used for fully functional days bound trial versions. Using this will enable use of these time bound period over and over again. This can be done using a simple 500KB (Approximately) application called as “Sandboxie”.
According to the its website “Sandboxie” lets you run your programs in an isolated space which prevents them from making permanent changes to other programs and data in your computer. Under the supervision of Sandboxie, an application operates normally and at full speed, but can't effect permanent changes to your computer. Instead, the changes are effected only in the sandbox. Wow! 
Here I am going to show you with an example on how to use it for bypassing time bound trial version software limitations. I used Mediatwins AC3 tools pro which offers a free 15 days, fully functional trial version to test and try its functionality. After 15 days it doesn't allow you to use it unless you enter a valid registration key. Uninstalling and Reinstalling also does not work after your 15 days are over. Lets see how it works:
STEP 1: Open Sandboxie Control, Click on the Sandbox option, then hover your mouse to DefaultBox –> Run SandBoxed and then click on Run Any Program.
STEP 2: This will open up a new option window which will allow you to run any exe file sandboxed. Click on Browse button to select the application you want to run. And then select the exe of the trial software you want to run. In our case we select the ac3tools_install.exe that is the installer for AC3 Tools Pro.
STEP 3: Click Open button and installation begins. Proceed with the installation steps as you normally do while installing any application.
STEP 4: As soon as you hit Finish, the application starts running. It presents you with the normal trial mode window. Just click on Continue trial button to proceed.
STEP 5: Notice the [#] marks in the Title bar of the running application window. These marks tells that the application is running Sandboxed and no changes have been done to your system.
STEP 6: Now if we navigate through the File and Folder in the Sandboxie Control Window we can see what all files and folders this installation have made changes or created new. Also notice the RegHive under the User Files section. Actually this is where the trial version store the encrypted settings which doesn't allow us to run them after the limited time period is over.
STEP 7: Now go ahead and use the software to its full and after you’re done, Exit the program and Click Sandbox –> DefaultBox and click Delete Contents.
STEP 8: This will open up a new window and delete all the files created, Press the Delete Sandbox button to fully clear the contents.
STEP 9: If you now open your programs menu you will notice that there has been no change. :)
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Using this method you can run any time bound application again and again without worrying about the time period limitation. I’d also like to let you know some known issues that I came across while working with Sandboxie. One is that sometimes it fails if we run heavy applications – I ran Firefox 3.0 with many add-ons and it failed when the RAM usage was around 750 Megs. Maybe this one is due to my metal configuration but anyways this is wht i found. Another thing is that, If you have already installed trial version on base machine and its time period was over, now if you try to install it again using Sandboxie it will not run. This is due to the fact that the Program already made entries in the Windows Registry Hive which is used by Sandboxie when it loads the application.
Please leave comments if you want to discuss or need help!
(Want to Install/Use your favorite applications but do not have administrator privileges to do that… Then please read http://abtevrythng.blogspot.com/2009/08/using-installing-applications-without.html for a workaround)
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