When you "removed an old hard drive," was this an additional drive connected to the ribbon cable, leaving just one hard drive connected? If so, and if the remaining hard drive is a Western Digital, its configuration jumper must be moved to master/single (from master w/slave present). If you replaced the original hard drive with another, the same configuration rules apply, because Cable Select isn't supported. The G3 will only recognize 128 GBs of capacity, due to the onboard IDE controller. Once installed, the hard drive will need to be formatted as a Mac OS Extended (HFS+) volume, which requires booting from the Mac OS installer disk or a bootable Mac floppy disk containing the utility "Drive Setup." I assume that this G3 is a beige model, as opposed to a Blue & White tower with native/onboard USB support. When connected to a USB PCI card, a USB keyboard isn't recognized until after the USB drivers are loaded, which is too late in the startup sequence to zap the PRAM. Additionally, the battery voltage reading is too low, and a very weak/dead internal battery can cause startup problems (as well as the incorrect date/time). The battery can be purchased here, as well as from other online dealers. You can also check any battery specialty retailers in your area, because it's used in alarm system components. Although Radio Shack carries a comparable battery, it's incredibly over-priced.
