Forever Uploading

hi… my arduino is taking ages to upload even just the basic blink example sketch. how can i fix this??.. it worked perfectly well before this , in fact, this morning.but suddenly, i keep getting this display

Check the obvious things: correct board, correct voltage (if applicable), correct port. Double check the port against the Device Manager in Windows (assuming you are using Windows 7/8/10).

Unplug the device to make sure it disappears from the Device Manager. And reappears when you plug it back in.

Reboot your PC whilst clicking your heels three times saying "There's no board like an Arduino" If you can hold a dog called Toto whilst doing this it will be more likely to work. ;D