TUTORIAL - Re-restore IOS 5.x on iPad2 and iPad3 using redsn0w and SHSH Blobs
Problems like the one you are describing are almost certainly related to your PC. Interruption to the communications are a good indicator that something is interfering with the process. Anti-virus, malware, Windows Defender, firewall etc. are usually to blame.
It could also be the use of a bad USB port, hub, incorrect cable, etc. (using a cable that was not for the iPad can often have adverse effects on restore operations - particularly older iPhone or iPod cables). Finally, ensure you have the latest iTunes as the drivers need to be current.
Disable as much as you can before you start, ensure you are connected directly to the motherboard (no hubs), and try again. If you still can't get it to work on your PC, the best bet is to try someone else's.