I would recommend 3 things:
1. Keep a copy of your project on Dropbox. I do this with whatever I'm working on, since it's how I transfer the project between PCs. This is free if you keep the data stored on Dropbox under 2 GB in size.
2. Purchase an inexpensive UPS, if you can afford one. A cheap one runs $60 or so. You don't need a lot of power, just enough so if there is a prolonged power outage, you can cleanly close out of your programs and cleanly shut down your PC. Do NOT assume "I closed RPG Maker" means "The RPG maker project has been completely written to disk."
3. Purchase an external USB key or drive. It's a good idea to schedule automatic Windows backups. In Windows 7, you can schedule automatic, incremental, weekly backups to a USB HDD, including a system image. If the system is hosed, you can either partially restore or, from the Windows 7 boot disk, restore the system image. This will preserve everything on your system, at least since the last backup.