Utilities on thiz page:
- fixing filez
- checking files for errors
- reconstruct missing files

Utilitys for fixing downloaded files

1 - Zidrav - more info
2 - WinCRC - more info

Personally I like Zidrav the most
to download one of them click on the link below
download Zidrav
download WinCRC

Reconstructing Missing Files

1 - Mirror - more info Mirror/SmartPar allows the recreation of (missing) files.
2 - SmartPar- more info & download
3 - FSRaid - info & download
4 - QuickPar 0.6 (can also handle PAR2 files) download QuickPar-0.6.zip
generic info (soundforge)

in case you are having trouble with the above sites, a mirror: Smartpar_0.13d1.zip   FSRaid_2.8.0.rar

Utilitys for verifying downloads

SFV - (usefull for small files (<20MB)
   pdsfv - more info & download here
   Easy SFV Creator - download

MD5 - (usefull for large files
   md5summer more info (& download) here
   Easy MD5 Creator - download


Download MD5 v1.1.0.19 here
Download pdSfv v1.2 here

--= the difference between SFV & MD5 =--
FYI, MD5 uses 128 bits (SFV only 32 bits ) and has better avalanching than SFV
In english: better avalanching = even a single bit of difference will make significant impact on the output.
Now to be concrete, MD5 are used to verify large files (e.g. ISOs), while SFV is normally more than enough for eg. the 15Mb files used as standard in releases...