Reinstall Photoshop Elements.

if you purchased from (or registered with) adobe, check your account for a download link, https://accounts.adobe.com

otherwise, what version?

The same way you did the first time... put the disc you purchased in the drive... or use the download that you should have copied to an external device to guard against a computer crash

Download the 'trial' and enter your serial number to activate

https://helpx.adobe.com/download-install/kb/photoshop-elements-downloads.html

IF/When you do have a download, be sure to copy it to AT LEAST one external device
-since Adobe does sometimes remove old versions from the server
-a usb flash drive or external hard drive, or write to a DVD
-plus a text file containing your serial number if you have a serial number program

Let me move this to the Download & Install forum for you, which is the appropriate forum for your question.

The Using the Community forum is for help in using the Adobe Support Community forums, not for help with specific programs, installation issues, or account issues such as subscription questions or billing problems, or generalized questions about Creative Cloud services.

* Product questions should be posted in the associated product community.
* Installation questions should be posted in the Download & Install community.
* Account issues, including subscription questions or billing problems, should be posted in the Account, Payment, & Plan community.
* Questions about the Creative Cloud desktop app or general questions about apps in the Creative Cloud should be posted to the Creative Cloud Services community.