It has enough power to run the PC but look for something with more power if you can. Many places locally will carry inverters (mine came from walmart) and if it's not strong enough you probably could return it. I have a 700 watts maxx inverter which runs my PC fine. I sometimes start my truck up for a few minutes if I'm using it for over a half hour but I've yet to have the battery voltage drop enough to sound the alarm on the inverter. As for running the vacuum I'm pretty sure you won't be powering a shop vac with that inverter. If you get a larger inverter then you can run many shop vacs. I have a 4gal 5hp rigid which is 9amps. My 700 watt inverter will power the vacuum in a pinch. The vacuum does run slower but once when my generator wouldn't start it saved the day. I've used it a couple of times when I had it set up for the PC and needed to vacuum up something quickly. If I was going to run the vacuum off it regularly though I'd get a larger 1200 watt inverter.
I don't know that much about inverters. I one time bought a 2000 watt inverter which I returned. I couldn't get it to work. I wasn't sure if my battery was insufficient or the inverter was defective. I had got it from a place 40 miles away so trying another one wasn't something I wanted to do.
I think using an inverter for vacuum is a great idea in that it is quiet, saves gas and wear on a generator. I was talking to a customer that rides bikes and joked around that since most of my work was in an office complex within a mile of my house that I could get a little pull behind thing for my bike and get rid of my truck. A deep cell battery, invertor, vacuum, ONR and I'd be set. Heck I bet there are ways to get the bike to recharge the battery.
