Scanning photos

I'm trying to scan a big box of old family photos, to preserve them and share them with family. But it's not as easy as it sounds. My scanner defaults to 200 dpi, which isn't very good, so I have to override it with a higher resolution setting for every single scan. However, the scanner doesn't operate very well at higher res. It takes forever, and sometimes refuses to scan the entire photo. And at this moment it seems to have had a meltdown since I can't get it to work at all. This is especially frustrating because it's a brand new scanner and I thought it was the highest quality scanner they had at Best Buy.