If you cannot open an Excel file and see Excel cannot open the file because the file format or extension is not valid error, see this post.

If Microsoft Excel opens a Blank screen when you open an existing file, then you can stop Excel from opening a Blank workbook or sheet.

When you're reformatting a drive, memory card, or flash drive you need to pick a file format. If you see FAT32, exFAT, and NTFS, but don't know which one to pick, here's what you need to know.