My bb 8700g, after wallpaper inst, comes out and doesn't loads OS (is resetting by itself). No connection may be used for remove/clean/upgrade SO. Last solution is a hard reset (i think), but nobody knows how to do it: somebody says to use ALT+CAP+DEL during start-up, somebody indicates a reset switch under battery (?), sb says to take out the battery during start-up... no solution was googd.
Does sb knows how is possible to reload (new) SO, out of usb connection?

Welcome to the forums.

How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ

What to do next if Jl Cmder will not connect and wipe - BlackBerryFAQ

Is not possible in my case apply JL_Cmder cause the bb doesn't loads SO at starting (...always resetting by itself) and usb port isn't recognizable by JL_Cmder. So I must apply a hard reset (if exists!).

Then you need to follow the 2nd link John Clark gave you above... if Jl_cmder does not work.

The ONLY hard reset for a BlackBerry is to remove the battery and replace, while the BB is powered on. There is no switch under the battery, no other way.
How do I reset my BlackBerry? - BlackBerryFAQ

Good luck.

well done John Clark!!! second link was the solution... but very very usefull were tips written by "acnst" about loading SO in command line and while usb port not recognized... Thanks to everybody and excuse my english... studied 30 yers ago!!!