My Asus M51AC PC in its original tower case was suddenly and unaccountably completely lifeless, save for a slow-flashing red LED light controlled by a switch on the motherboard (marked as GPU POWER BOOST). No fans, no nuffink. Having tested almost every component, I was on the verge of buying a new PC on the grounds that the mobo had failed... Unlike most PC’s, the main PSU power cable on an Asus M51AC is not connected directly to the mobo. Instead, it is connected to an internal green circuit board that is largely hidden from view below the DVD tray. A short power cable then leads from that circuit board to the mobo. The PC was resuscitated by simply bypassing the green circuit board. Instead of connecting the main PSU power cable to that board, which originally had a power cable connection to the mobo, I connected the main PSU power cable directly from the PSU to the mobo. Everything then worked perfectly - except for the UPS, the removable (portable) rechargeable battery and the WiFi charger tray on the top of the case. When I tried to use the battery independently of the PC, it would neither charge nor discharge. Whether the failure of my PC lay in the battery, the circuit board or both is unclear as I have not tested the system with a different battery. I am now content to run my Asus M51AC PC without an internal UPS - and my smartphone is not smart enough to use a WiFi charging system...
I would suspect the battery in that ASUS Power Pack. If it has shorted internally (a common fault as batteries age), it could prevent power from getting past it, keeping your computer from booting. So if willing, open the Power Pack and see if you can determine the battery specs. If lucky, it might be a common SLA battery you can get for a reasonable price from a battery site - instead of paying a fortune through ASUS. Nice troubleshooting work, BTW!
