hi stummies0,
low disk space error may mean not enough free space for your disk swap file to operate properly. Google swap file to see what it does, preferably at microsoft.com.
You likely need to remove some important personal files to some sort of back up media to do this.
Use at least two types of backup media to back up your files in case one of the drives/media becomes damaged or corrupted. Some such are USB flash drive, CD/DVD, external hard drive, BluRay, etc.
Open My Computer by double-clicking it, and right-click the drive with the space error issue. Select Properties in the drop-down list. If it is almost full (little free space left), then that is your issue, and can only be resolved by removing large or unwanted files to backup.
If it (is) not close to being full, report back.
[EDIT:] Strongly suggest use copy/paste for any operation, as cut/paste is sometimes not reliable; if cut/paste fails, the entire file is lost. You can delete any files after they are properly backed up at the end of your copying operations from the original source drive.
