I hate to disappoint you but I don't know that much about hosting a web server.
I will state this. Normally servers have redundancy on things like power supplies and storage. Storage is usually run as an array of some sort. The more mission critical the data the more secure the hardware must be. The RAM should have some sort of error checking built in. That requires a motherboard that can support
Servers usually have two power supplies, lots of RAM and many bays for hard drives. The hard drives may be hot swappable. The technical aspects go up from there.
A normal personal PC will not have two power supplies and will have limited storage with out the kind of RAID array you should have. So, no, your PC probably won't make a good server.
See the links below.