Jim, It cannot be installed anywhere except your main pc drive. I've contacted their support team already.

Karel, from the vendors website:
https://www.filerestoreplus.com/download.php

Release Notes
Version 4.0.24.405
New Features:

Added Trial mode which is limited to recovering 5 files, maximum file size 50MB or up to 250MB worth of files, whichever comes first.

It does not say the trial mode expires, after some number of days, so one ASSUMES it reverts to trial mode and those limits on operation will apply.
TK

P. ity, if you have an EXT2,3,4 file system driver for windows so windows enumerates a drive letter if the program has a deep scan mode? It should be file system agnostic as it should look at sectors and not filesystems and recognise file headers like JPG or PNG or GIF headers for example and try using the data in the headers to try and retrieve contiguous sectors to recover the found files data. If you are talking about using it WINE under linux it is unlikely that any windows based file recovery program will work under WINE as the underlying hardware abstraction layer is not compatible between the two systems. If it's not file system agnostic on deep scan or has no deep scan then pfft they need to try harder!
TK

Partha Mandayam, see to it that you have more than one copy of each important file and store every copy on a different hard drive or USB stick, in a different location. Because your house may get flooded, burned down or buried in a land slide.

Mail yourself and next-of-kin scans of important files.

Partha Mandayam,

(from their website)

If you already have FileRestorePlus installed, open it and run a scan for deleted files.

If it's not installed, then download it to a USB thumb drive or any other removable media and run it from there.

Partha Mandayam,
Use software designed for that situation. A lot of it is offered here, keep a watch for it.

"If your hard drive crashes, then even the filerestoreplus program will be gone!!! THen how will you restore?"

That's not what any file recovery app is for. You basically have 2 options to save your stuff in case of a hard disk/SSD failure... 1) as gergn posted, you can save copies of the most important stuff elsewhere, then if the hard disk fails reinstall Windows & your software on a replacement hard disk. 2) perform a disk/partition image backup, which is a clone of your hard disk usually stored in a VHD [Virtual Hard Disk], that you'll want to store copies of elsewhere. You can then restore that backup to the replacement hard disk. You would of course need to keep that backup current.

Apps like FileRestorePlus work because all the files on a hard disk/SSD are listed in a sort of table of contents or index, and if you delete a file only that file's entry in that index is deleted. A file's entry in that index may also become damaged due to a disk or OS error. In those cases FileRestorePlus finds the data still on the hard disk & tries to assemble it into files, hopefully including the lost file(s) you're after. The tricky part is that anything written to the hard disk or SSD containing the lost file(s) may overwrite that data, making it unrecoverable. SSDs also have an automated process called TRIM, that deletes the data from deleted files. If the lost files are on the system disk partition that also holds Windows, your best bet is to shut down, boot to another OS, e.g., a copy of Windows on a Windows To Go drive you set up using Rufus, and run FileRestorePlus [or similar] from that. That way Windows isn't writing to the disk with your lost files and potentially overwriting them.

Partha Mandayam, if your hard rive "crashes" it means the heads physically impacted the spinning disc(s) and may no longer even operate, you may need to replace the head assembly or drives motherboard etc in a clean room lab.... silly toys such as this will be the least of your concerns... once the physical drive operation is restored you'll want to image the entire drive surface to a known good drive for inspection and data recovery from the image file which this and most other retail recovery programs simply cannot handle.
TK