It depends on what was your version of PSE. For PSE11 you can download the trial version from Adobe site and use your serial number to activate it for perpetual license.
For some older software, there are links posted on third party sites that links to Adobe trial software for old products and again you can use your serial number to activate the product.
As to official Adobe replacement disks, I did have a direct link but I can't find it right now. Perhaps I will find it in about two days time. There used to be a handling fee but I won't reply on these links because Adobe doesn't like dealing with small amounts!.