You should really learn to evaluate all the expenses and run the numbers, Cha Yang.

I think it was caused by some run-off issues with water.The bottom line is I need to get it fixed.  

If this investment doesn't hurt me in the long run I think I'll be lucky.

I would have the ducts cleaned, furnace/AC system cleaned as much as possible, change the filter, and then run an ozone machine with fans set up to circulate the air for 48 hours.

I am so eager to invest, but I worry that if I started investing now (keep in mind I have little knowledge in real estate and have no money to put down) I will run into problems and I don't think I can afford that. 

@Ryan McEniff based on my education and training when analyzing a deal I use the following for operating expenses: Check with the local area you are buying by asking the local experts, but as someone who is a real estate Broker in CA, our average closing costs on the buy side for a buyer will run between 2%-3% of sales price (most of that comes from lender origination fees). 10% vacancy (most deals I see when being offered for sale are between 5%-8%, but if it pencils with 10% I know I'm probably covered on vacancy)10% for property management (until I know exactly what the PM fee is then I would modify, but average is 8% to 10%)5% for R&MActual Property TaxesInsurance (Get quotes from 3 companies and take the average)Landlord Utilities (12 month average.

I'm sure the buyer is an investor ... ask him if you can tag along on the deal and help out here and there ... check in on the job site from time to time and take pictures for him, run to home depot, etc.

Can the cables be run underground, and  the transformer put in a standard ground box? 

What do you think the long-run upside in those neighborhoods could be?

Looking at listing may not need full rehab, new roof and water heater done, 3br in neighbor run 900 to 1000, rehab for low maintenance, try to buy as low as you can , look at comps, probably could go in as low as 38-42 with good agent and stress as is, maybe a few agents here to help, get one to give you good numbers not listing agent numbers , street is a nice one for area, not much back yard or parking but nice front, before you close make sure vacant  contingent, if numbers work I would do it, the are predicting an abundance of rentals avail next year with building craze but keeping expense low you should be safe, remember don't rehab as if you are living there, think durable and repaintable, number should go into systems and structure first, elect,heat,walls, windows,floors,plumbing, if you use a contractor go with one you know or work with someone in area to keep an eye on progress, good luck at least you know some of the history of the property