I can answer your questions, I purchased one this last Wednesday. The hard drive is removable, just as it would be on any PC, just some screws. The motherboard is a MSI (Micro-star intl.) MS-6701, with the SIS648 chipset. The machine has a 40x Sony CD-RW, a 16x Sony DVD-ROM, a 128mb Geforce4 Ti4200, but with operational AGP 8X, 256mb of PC2700 Samsung. Very quiet, one P/S fan and one (80mm)? fan slowly blowing down on the P4-2.6ghz chip. It comes with the modem installed in a PCI slot, the AGP card is removable, and NOT built on the mainboard. It does not come with a floppy disc drive, but has a slot under the sliding front cover for one, and there is a floppy port on the mainboard, as well as bios support for it. It comes with onboard sound (which is OK), a built-in 10/100 NIC card, the AGP card comes with dual monitor support. The slide down front cover has slots for Compact flash, smart media, memory stick and SD/MMC. It also has 3 USB 2.0 ports on the front as well as , (I believe, firewire connection). On the front it also has a joystick port, along with composite, s-video outputs, microphone and speaker outputs. It is a 250w fortron p/s. It is a little small on the inside, but has another slot for an additional stick of memory.
This review isn't perfect or guaranteed complete, but it's a nice system for the money..