If Vista was wiped off the drive then you need to contact Acer for the installation
media so you can put Vista back on the drive. The laptop needs the drivers and
other utilities that Acer would provide on a OEM installation disk,
In case the Vista installation was only corrupted these might help.
Try Startup Repair from the Recovery Console (if you have one) or from a Vista disk - if you do
not have a Vista disk you can borrow a friends (they are not copy protected) or make one. Also
your System maker will sell the physical disks cheap since you already own Windows. (This may not be true since you are not the original owner
and you may not have the product ID for Vista.)