Thanks for providing those additional details. The MegaGlest 3.9.0 installer for Windows you have downloaded seems to be 254,255,092 bytes, this is the correct size. Still, it s strange that it would crash during the installation process, this is the first time this was ever reported.
Which anti-virus software do you run there, if any? Do you run additional anti malware tools - if so, which?
Please click on the Start / Windows button and type
winver into the search box and press enter to run it, then take a shot of the newly spawned window.
Do you experience similar problems (installers failing, programs closing unexpectedly more than they do for other people) regularly?
When is the last time you ran a full AV scan?
Is Windows Update configured to install updates automatically?
Are there recommended Windows updates you prevent from installing on purpose?
These questions / tasks are a bit more difficult,
catch me on IRC if you need help with them:
When is the last time your anti-virus signatures were updated?
When were the last Windows updates installed successfully?
Which file system is D: formatted with, and is it stored on an internal hard disk drive (HDD), and on the same HDD as the C: partition?
Do a full file system check of D:, does it find any errors?
Do a SMART long self test of the HDD which D: is on, what are the results?