try this here and see what happens...
1. turn off the user account control - control panel\useraccounts\ - you will see it at the bottom uncheck it. then restart the computer.
2. uninstall both trial and/or wb program you have installed completely.
3. open program files/stardock/objectdesktop/ and delete the folder for windowblinds there. Do make a backup of your wb's to a folder in another place other than in the program files.
4. do this to get rid of temp files go start and run from start menu. in run type %temp% and say ok. when the folder opens delete everything there as this crtl+a ... what does not delete then just leave it.
5. open c: drive go to windows/prefetch folder and do the same as with temp folder delete all ctrl+a and close the folder. restart your computer and then go to sdc and reinstall wb again. That should work unless you have something turned on that is blocking the install.
Be sure the firewall and anti-virus is off and that there is no spyware program running.
the other thing that can fool with the download of the program is the internet options for IE7. Be sure you set the security to the default levels for all zones in internet options. this can be found in tools for IE7 or in the control panel.
good luck and I hope this works for you.
SGT