downloaded many times. tried all suggestions. at first the error said that there is problem with setup_painkiller file, now it just says that fileS are corrupted.

tired of this. can i get my redeem code back, plz?

The problem is most likely on your side, either your machine or your internet connection. Many, including myself, have downloaded the files and they are fine, so the files on GOG's servers must be okay, though they are large files which increases the chance of corruption if your internet isn't stable or free from interference.

If you've taken the usual measures such as turning off any anti-virus during the download, letting the download go on its own without using anything else that requires internet, and tried using the download links as opposed to the GOG downloader then I'd recommend trying on another machine with a different internet connection. You can always move the files to your own machine after the download by using an external drive or burning the files to disc.

You won't get a refund or redeem code back as the games are DRM free so once purchased they are owned. There's nothing to tell GOG whether they have been used or not, or whether they work on your machine or not, and they don't require any authentication with GOG, and so for these reasons GOG have to have a no-refund policy. It is in their terms and conditions.

For reference, here are some details about the installer files that I have for Painkiller Black (version 1.0.0.3 of GOG's installer):

setup_painkiller_black.exe
Size: 2353009 bytes
MD5: 04779d4d56e828daff8f82ba239d96a3
SHA256: e47afd284a7d7a286ee854bf07b12ceeeedcee020dae05d656ee5b6caf417cae

setup_painkiller_black-1.bin
Size: 2097646848 bytes
MD5: 7db45f6fb84caa50f4b4679a63f30418
SHA256: 810cc709df74a9de1c9140d955fb118fad956da83a457183bde15692d93f26fd

setup_painkiller_black-2.bin
Size: 1710504737 bytes
MD5: 23f6f6b2078b5b909eaacff0a8238586
SHA256: b8ce98b8cebaaaa4c9b5ce6a466c017ce3f0f6191e79ca2333b0cafd2edbd701

My advice for bigger games like Painkiller. Use the GOG downloaden it solves a lot of problems.

I have tried the GOG downloader as well. I am getting gaps in the progress bar and when the download is finished the part 1 bin file is incomplete. A screenshot of the downloader is shown below. I thought part of the reason for the downloader was to redownload missing blocks. So far it does not appear to be doing this. After the progress bar is completely filled it doesn't got back and fill in the gaps.

I have tried downloading in two different locations with both wireless and wired connections using Windows XP and 7 with the same result. The first large file is either corrupt (direct download) or unassembled (downloader).

Quite frankly it's getting old. i would love to play the game, if only it would allow me to do so.

Restarted the GOG downloader after it finished to fill in the gaps in the progress bar. This got the setup_painkiller_black-1.bin file on my system complete and uncorrupted. At the time I couldn't say the same about the setup_painkiller_black-2.bin file. I started a standalone download of that file last night and left the computer alone. I tried it this morning and it actually went through the install. Not bad, but I'm glad I didn't pay much for the game.

Now that the game has downloaded and installed properly, I have burned it to a DVD. It installs from that too, which is good - when I copied the files to a flash drive, they were corrupt again.

I think something's wrong either with your memory or with your mainboard. Test it with MemTest or a similar tool. From the way you describe it, the problem is unlikely to only affect the Painkiller files. Is your system overclocked? Is your machine's ventilation okay?

My system is not overclocked and the ventilation is OK to my knowledge - little or no dust in the sytem. I have had bad luck with overclocking in the past, so I don't bother to now. It could also be the flash drive - I have had it for a few years and it is used quite a bit. I'll also test the memory once I get home.