Hi Rajeev,
As a home inspector, I would be looking at the following in a place that old:
Structure: what is the foundation made of? (Stone, brick, etc), is there cracking? Signs of leakage? Are the foundation walls bowing in? (Horizontal cracks are a big deal, vertical cracks not as much), condition of main beams (if it has wooden structural components, is there wood-destroying insect damage?), definitely get a termite inspection. They're cheap.
Plumbing: Is the pipe galvanized (silver) or is it copper? If galvanized, expect problems with pressure in the future, and expect to replace it, are there any improper connections (i.e. Galvanized to copper w/o a di-electric fitting)? Leaks?
Electric: Does the panel have fuses or breakers? If fuses it will likely need updating, panel have double taps (2 wires to same breaker)? Aluminum single-strand wire (fire hazard), is the wiring in the house modern (conduit/Romex sheathing vs Knob and Tube), are outlets grounded? Are there functioning Gfci's where needed?
HVAC: how old are the heating/cooling units? Do they function well? Does the furnace/boiler vent properly (to avoid carbon monoxide issues)? Is the fireplace/chimney in good repair and clean?
Interior: are windows old or newer? Painted with lead paint? If double pane are all seals intact? Do doors open and close as they should? Are there door stoppers?
Are walls and ceiling drywall or plaster? In either case, look for water stains/signs of mold. Are floors reasonably level? Is there significant settlement cracking anywhere?
Roof: how many layers? More than 2 is bad, 1 is much better, is it properly sealed? If flat, does it have proper drainage/terminating strips? Do the downspouts discharge near the foundation (aim for 3-4 feet away)?
Exterior: is the soil/ walkways graded away from the house? Damage to the siding? Soffit/fascia properly clad?
This isn't a complete list, but it should keep you out of trouble :) let me know if you have any questions.
Joe Ziolkowski
On Target Home Inspection
708-274-7279
www.OnTargetHomeInspection.com