You might have a chance - it depends what stage it was at.
Rt click it > properties,Unblock,Apply,OK.
Burn it to cd/dvd as an image ( not as data ). DO NOT FORMAT THE CD/DVD.
Windows 7 has an image burner built in - otherwise get imgburn or similar. SetupImgBurn_126.96.36.199.exe <- ImgBurn Downloads | Software - Digital Digest
Boot that cd/dvd on the sick machine.
When you get to the desktop, give it 30 secs to settle, then click the Partition Wizard icon.
Select partition recovery - do a quick scan of the whole drive.
When it has finished, it lists the partitions it has found.
tick ALL the partitions you want to keep, OK, Apply.