I found this but no mention of PSU:
CPU: AMD Sempron™ 3100+ Processor
(1.8GHz, 1600MHz system bus, 256KB L2 cache)
Operating System: Genuine Microsoft® Windows® XP Home (SP2)
Chipset: NVIDIA® Crush 51
Memory: 512MB DDR (1 × 512MB) 400MHz (PC3200)
Expandable to 2GB
Hard Drive: 100GB (7200rpm, 2MB cache)
Optical Drive: 16x multiformat dual-layer DVD±RW drive (up to 8.5GB with dual-layer media)
Media Reader: 8-in-1 digital media manager (Secure Digital™ (SD), Smart Media, Micro Drive, Memory Stick®, Memory Stick Pro®, Compact Flash, Multimedia Card, USB 2.0)
Video: NVIDIA® GeForce®™ 6100 GPU
Up to 128MB of shared video memory
PCI-Express® (PCI-E x16) slot available
Sound: 6-channel (5.1) AC'97 audio
Network: 10/100Mbps Ethernet LAN
Modem: 56K ITU v.92-ready fax/modem
Peripherals: Standard multifunction keyboard, 2-button wheel mouse, amplified stereo speakers
Ports/Other: 5 USB 2.0 ports (1 in media manager, 4 in back), VGA external connector, serial port, parallel port, 2 PS/2 ports (keyboard and mouse), 5 audio ports (2 in front, 3 in back)
Dimensions: 14.25"H x 7.25"W x 16"D
Weight: 22.5 lbs
Then found this:
Product Description
- 480W Power Supply Replacement PSU
- One (1) 14-inch SATA connecter
- One (1) 14-inch ATX power connector (supports both 20-pin and 24-pin configurations)
- One (1) 14-inch 12V P4 ATX power connector (4-pin)
- Two (2) 12-inch large power connectors (4-pin)
- Two (2) 6-inch large power connectors (4-pin)
- One (1) 6-inch Small power connectors (4-pin)
- Quiet/Low-noise Operation
- Supports latest Serial SATA Adapter
- Energy Star Efficiency
- Over Power and Voltage Protection
- Designed by Logisys
Dimensions:
Depth: 5.5"; Height 3.5"; Width x 6"
Replacement for:
Bestec ATX-250-12E, Bestec ATX-300-12E. P/N 1670, 1763, 100744, 100889, 100929, 129074, EM-2309, EM-2423, EM-2450, EM-2369, EM-2436. Also replaces many other models.
AC Input:
100~120Vac 10A
200~240Vac 5A
DC Output:
Load Min Max
+3.3V 0.3A 28A
+5V 1.0A 36A
+12V 1.0A 16A
-5V 0A 0.5A
-12V 0A 0.8A
+5VSB 0A 2A
And then found this:
Bestec ATX-300-12ED - 300 Watt ATX Power Supply
Product Number ATX-300-12ED
Key Features:
Common Emachine replacement power supply. See chart below.
Product Description:
This power supply is a "special" one. The Bestec ATX-300-12ED 300 watt power supply replaces several hard to find emachine power supplies. Take a look at the chart below the picture of the power supply.
Looking to upgrade? Try this power supply. It's 630 watts and provides needed power when upgrading video cards or adding devices to your computer.
Technical Specs:
ATX Form factor
6" Wide X 3.5" Tall X 5.5" Deep
One ATX 2.03 connector (20 pin)
One 12V connector for P4 motherboards
Four IDE 4 PIN connectors
Two Floppy 4 PIN connectors
One AUX connector
Output Max. Load
+5Vsb 2A
-12V 0.8A
+12V 15A
+5V 30A
+3.3V 28A
I think we can safely say he has a PCIe x16 slot and no more than 16 amps on the 12V rail.
As far as Nvidia cards this means you'll be limited to an 8400 or 9400 series card. You might be able to run a 8500/9500 series card but it will be touch and go with your power supply.