The best thing a UPS does is keep the PC alive during brief outages. It's not meant to be a power supply one can just keep on using when power goes out for any length of time. The critical quality of a UPS is just as the first letter stands for (Uninterruptible). It switches instantly to its battery. That's not true for an inverter. Those are meant as backup for lighting, sump pumps, etc. I'd not think there's any way to use an inverter as a replacement for a PCs UPS.
I do have a Dell new inspiron i4 desktop. I do have home inverter luminous 850 with battery of 150 ah. I wanted power supply to the pc from the inverter, coz i do not have extra ups for my pc. can i do that and is there a voltage stabilizer for the pc required and if required which stabilizer should i buy. plz help me. thanks in advance