Deep Sky Stacker wont align.

[Dakar234]

Since i re-installed windows and all the software and programs that weren't backed up DSS has started stacking pictures like this (just the raw image, didnt edit or anything). I stacked 450 ISO400 .8 exposure. It stacked them all, but didn't align them properly. This is something new since my new OS install, and i re-installed DSS 4 times just in the off chance it was the program.

 I recently stacked pictures of the Ring Nebula and it worked with 300 pictures, but any more and it wouldn't align them. The photos i used in the picture above were slightly out of focus....but you'd have to zoom a good bit to notice (and no more than other images that have stacked just fine). As far as i can tell all of the settings are the same(i just use the default settings, but I've messed around with them a bit and it hasn't helped). And DSS said there were about 100 stars that could be used to align. 

Anyone else had/have this problem, anyone know how to fix it or whats causing it?  

- Thanks. 

[martin_h]

Have you tried with a shorter stack of say, 100? If that works do 4 stacks of 100 and then stack the 4 stacks.