Adobe Acrobat creates custom PDF files that are compatible with other word processing applications, such as MS Word, Excel, Sharepoint and more. The product offers a trial to let you test its efficacy before you make the actual purchase for £129 (as of 2010). If you've been unable to test your product during the trial period and it's now expired, you might want to extend the trial duration to properly evaluate it. Restoring the trial period is simple, and just requires a few registry tweaks.
Open "Start" menu from the bottom System Tray, and click "Run." A small dialogue box will open. Type "%SystemRoot%\system32\restore\rstrui.exe" in the dialogue box, and click "OK." This will bring up the System Restore application, which will be used to reset Acrobat 9, after the product's trial expires.
Click "Create a Restore Point" on the "Welcome to System Restore" screen. Then, click "Next." Type any name for the restore point, for instance "Acrobat Reset," on the "Create a Restore Point" page. Then, click "Create." Click "Close" after creating the restore point.
Install Acrobat 9's trial version now, and wait for it to expire.
Go to "Start" > "Run." Type "%SystemRoot%\System32\Restore\Rstrui.exe", and click "OK." Again, this will launch the System Restore application. You will now restore the system back to the point where Acrobat 9 wasn't installed on it. This would reset the trial period.
Click "Restore my Computer to an Earlier Time" on the "Welcome to System Restore" page. Click "Next."
Click the system checkpoint on the "Select a Restore Point" page. From the "On this list select the restore point" drop down list, select the entry you had named in Step 4 of the first section of this article. Click "Next," and then click "OK."
Click "Next" on the "Confirm Restore Point Selection" page. Your system registry will now be restored to the point where Acrobat's trial version was not installed on it.
Run the Acrobat 9 installer again, and follow the installation instructions. The trial version for the reinstalled application will be fully reset.
Back up any important data that you saved after the restore point. Restoring the PC back to the restore point will remove this data.