Do you know what model the motherboard is? You may be able to put in a Core 2 Duo which are more powerful than the Pentium D. This saves you having to buy a new motherboard as well as a processor.
Specifications
Part Number: 4006158RIntel (Coryville) 945G Motherboard
Specifications are subject to change without notice or obligation.
Feature Specification
Form Factor microATX 9.6 × 9.6 inches
Processor
* Intel® Core™2 Duo processor in an LGA775 socket with a 1066 or 800 MHz system bus
* Intel® Pentium® D processor in an LGA775 socket with an 800 or 533 MHz system bus
* Intel® Pentium® 4 processor in an LGA775 socket with an 800 or 533 MHz system bus
* Intel® Celeron® D processor in an LGA775 socket with a 533 MHz system bus
Memory
* Two 240-pin DDR2 SDRAM Dual Inline Memory Module (DIMM) sockets
* Support for DDR2 667, DDR2 533, or DDR2 400 MHz DIMMs
* Support for up to 4 GB of system memory
Chipset Intel® 945G Chipset, consisting of:
* Intel® 82945G Graphics Memory Controller Hub (GMCH)
* Intel® 82801GB I/O Controller Hub (ICH7)
Video Intel® GMA950 onboard graphics subsystem
Audio 6-channel (5.1) audio subsystem with three analog audio outputs using the Sigmatel 9220 audio codec
Legacy I/O Control Legacy I/O controller for diskette drive, serial, parallel, and PS/2 ports
USB Support for USB 2.0 devices
Peripheral Interfaces
* Eight USB ports
* One serial port
* One parallel port
* Four Serial ATA interfaces
* One Parallel ATA IDE interface
* One diskette drive interface
* PS/2 keyboard and mouse ports
LAN Support 10/100 Mbits/sec LAN subsystem using the Intel® 82562G Platform LAN Connect (PLC) device
BIOS
* Intel® BIOS (resident in the SPI Flash device)
* Support for Advanced Configuration and Power Interface (ACPI), Plug and Play, and SMBIOS
Expansion Capabilities
* Two PCI Conventional bus connectors
* One PCI Express ×1 bus add-in card connector
* One PCI Express ×16 bus add-in card connector
Instantly Available PC Technology
* Support for PCI Local Bus Specification Revision 2.3
* Support for PCI Express Revision 1.0a
* Suspend to RAM support
* Wake on PCI, RS-232, front panel, PS/2 devices, and USB ports
Hardware Monitor Subsystem
* Hardware monitoring and fan control ASIC
* Voltage sense to detect out of range power supply voltages
* Thermal sense to detect out of range thermal values
* Three fan headers
* Three fan sense inputs used to monitor fan activity
* Fan speed control