Acer Cloudmobile S500 specifiactions:
Other names :S500
GSM frequencies :850 900 1800 1900
Standard UMTS :900 2100
Type :Touch
Dimensions (W x H x D) :127,00 x 65,80 x 9,90 mm
Main display :Color / IPS TFT
16M colors
720 x 1280 px (4.30")
Internal memory :8 GB
RAM memory :1 GB
Memory cards : microSD, microSDHC (up to 32 GB)
Operating system :Android 4.0 Ice Cream Sandwich
Processor :Qualcomm MSM8260A
Processor clock :1,50 GHz
How to hard reset:
Warning! All data will be deleted!
1.Power off the phone
2.Press together volume down + power button until Acer logo will appear and the phone will vibrate after 2sec.
3.Once it vibrates, release volume down and push volume up
4.The phone will vibrate again, release volume up, it will boot in recovery mode.
5.Use volume buttons to select "Wipe data/factory reset" and then press power button to select it.
6.Confirm "yes"
7.Wait until the format ends
8.Select "reboot" and press power to confirm
9.Wait until the phone restarts
That's it!
Here is video how to hard reset: