Onetwo l brand new today tried to switch back on from standby making hideous noise not booting up

Can you post a picture of the machine?

most of the time on older monitors you can set the refresh rate in safe mode and that will, most of the time, resolve the problem otherwise time to purchase a newer monitor.

Beep codes are nice but you have to know who makes the BIOS to use them. Check the RAM and see if it is loose.

Try this link
Packard Bell oneTwo M3350 / oneTwo M3351 / oneTwo L5350 / oneTwo L5351 All-In-One Computer Service Guide

First is the set should have a 1 year parts and or labor warranty--second: in order to offer advice or give help I need to know brand and model number.

Likely the filter capacitors have a problem. Best to take this in for repair... it is ODD that there is noise with the standby switch is in standby... That makes no sense... In standby it appears that power is removed from the power amp high voltage so nothing should come through the speaker... Unles maybe one off the power tubes had a total meltdown which should have blown the fuse.

If your laptop is beeping it indicates a motherboard issue that can not be corrected without a technician. Since the laptop is under warranty I would return it with haste for exchange.

I have a similar problem with a Packard Bell OneTwo S PG4G1TU01 : when switching it on, it work a few minutes and suddenly shutdown, as a brutal power down. But the green light at the bottom still working. I have changed the extern power supply and now it work fine... The new power supply is a 90W model, not a 65W like the original one. Maybe it can help ?

Brand new today? Stop fooling with it now! Take it back and make them give you a machine that works. If you fool with it any more, your warranty will be of no value.

Thanks for your interest in FixYa.com

you ight have a BAD CPU, try checking it out on another pc or friends pc.