Tablet is not working for 3 years. Can it be repaired?

Hi,

Most probably the battery in the tablet has been depleted to a point beyond recovery and will have to be replaced.

You could try connecting the charger to the tablet and leaving it connected for about 4-6 hours and see if there is a remote chance that it might start charging the battery again.

If the tablet does indicate that it is charging, allow the battery to fully charge before attempting to turn the tablet on.

If this doesn't work you will have to replace the battery.

Here is a link to the ifixit battery replacement guide for your tablet.

Remplacement de la batterie du HP 7 1800

Search online for a suitable replacement battery, by looking for HP 7 1800 battery to find suppliers and prices that suit you best.

Hopefully this is of some help