All four DVD's to restore the original hard drive for the Acer Aspire One with Windows 7 partitions.  

Specifically for the model 532h 2527. but should work on many more.

World's sorriest implementation of the World's sorriest operating system.  This is for "purists" only.  Those who want a properly-functioning machine should bite the bullet and figure out how to force a load of XP Pro.

There are four NERO .NRG format ISO files. Burn all four to DVD's (trust me on this!) and boot to the SYS disc first,  from a USB DVD drive.  It will call for the RESTORE discs one and two,  then the LANGUAGE disc.  

Then, only six hours later,  you will be waiting while it sucks in the dozens of "free trials" and finally finishes and slows to a crawl.  GEEZ!  Get a LIFE,  Acer and Microsoft!   This is AWFUL!