Have Volvo Questions? Ask a Volvo Mechanic for Answers ASAP
Welcome, I'm Chris (aka Moose), my normal schedule online is around lunch and after dinner past midnight.
Can you check the voltage on the battery cables while trying to start to see if they are maintaining and showing around 12.6 volts. Since everything goes dead when trying to start this sounds more like a voltage issue than a theft system issue.
This is my 1st answer of what can be many. You the website and myself expect you to have a ~~~5 STAR EXCELLENT~~~ experience with my help. At the top of your screen is the rating box that you only get to use once. Please make sure to complete the mandatory rating when ready or reply and say "I am pleased with my answer". Not rating or rating 1-2 stars does not benefit you nor me in any way.