Don't worry about the two negative voltages. At least one of them (the -5volt line) is clearly bogus. Starting from several years ago, PSU's don't even have a -5 volt output. And a lot of the Windows software for monitoring PSU outputs do not handle negative voltages well.
Check the PC Health section of the BIOS or measure with a digital multimeter. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: +5 volts always on. The gray wire is really important.
It should go from 0 to +5 volts when you turn the PSU on. CPU needs this to boot.