Avid Pro Audio Community - Pro Tools LE 7.0 playback problems of virtual instruments and plugins

I am experiencing some playback errors with my virtual instruments and plugins with Pro Tools 7.0

I have just got this new computer (specs below) and have installed my copy of Pro Tools 7.0 onto it. I cannot find at the moment my 7.3 update installer (which I had previously been using).

After the install, I opened up a project I had been working on from a different machine, and when I went to play, the plug-ins/virtual instruments wouldn’t work, apart from the first few seconds of playback. I was using BFD Lite for drums, and the first two bars would play, and then it would stop.
I started a new project, setup a click track, and the click only played back for a few bars before stopping.

I am running a Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz PC (full specs below), Microsoft Windows XP Professional 5.01.2600 (Service Pack 2), a Digi 002, Pro Tools 7.0, 2 GB RAM.

Attached Peripherals: Digi 002 (firewire), USB external hard drives x 2, M-Audio Radium 61 keyboard (USB). I have the MIDI keyboard and one USB drive attached to rear of computer USB ports, and the other USB external drive attached via both USB ports at front of computer (one for power, one for data). I have tested playback with the USB drives attached and unattached – problem still occurs.

I have three internal hard drives;
Hard Disk (C:) : 149GB (NTFS) (160GB, SATA300, 3.5", 7200rpm, NCQ, 8MB Cache)
Video (E:) : 186GB (NTFS (200GB, SATA150, 3.5", NCQ, 8MB Cache)
Audio (F:) : 186GB (NTFS) (200GB, SATA150, 3.5", NCQ, 8MB Cache)
I am recording to the Audio drive, and have used it before fine with my old computer.

The default settings are still in effect. The only troubleshooting I have tried thus far is changing the Playback engine settings from the defaults. I adjusted the H|W Buffer Size from 512 both up to 1024 and down to 256, no change. I adjusted the RTAS Processors between 4 and 1, again no change. I adjusted the CPU usage limit from 85% to 40%, again, no change. The DAE Playback Buffer was adjusted from the Default 2 both higher and lower, again, no improvement.

Below is the Sandra report info:
SiSoftware Sandra

Computer
Model : Gigabyte P35-DS3
Workgroup : WORKGROUP
Host Name : westav-9b039735
User : Ed

Processor
Model : Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
Speed : 2.4GHz
Cores per Processor : 4 Unit(s)
Threads per Core : 1 Unit(s)
Type : Quad-Core
Integrated Data Cache : 4x 32kB, Synchronous, Write-Thru, 8-way, 64 byte line size
L2 On-board Cache : 2x 4MB, ECC, Synchronous, ATC, 16-way, 64 byte line size, 2 threads sharing

Computer
Mainboard : Gigabyte P35-DS3
BIOS : Award (Phoenix) F4 06/29/2007
Bus(es) : X-Bus PCI PCIe IMB USB FireWire/1394 i2c/SMBus
Multi-Processor (MP) Support : No
Multi-Processor Advanced PIC (APIC) : Yes
Total Memory : 2GB DIMM DDR2 DDR3

Chipset
Model : Giga-Byte P35/G33/G31 Processor to I/O Controller
Front Side Bus Speed : 4x 267MHz (1GHz)
Total Memory : 2GB DIMM DDR2 DDR3
Memory Bus Speed : 2x 334MHz (668MHz)

Memory Module(s)
Memory Module : Kingston 99U5316-017A00LF 1GB DIMM DDR2 PC2-5300U DDR2-666 (5-5-5-15 3-20-5-3)
Memory Module : Kingston 99U5316-017A00LF 1GB DIMM DDR2 PC2-5300U DDR2-666 (5-5-5-15 3-20-5-3)

Video System
Video Adapter : NVIDIA GeForce 8500 GT (16 SP 1.3GHz, 256MB DDR2 2x400MHz, PCIe 1.00 x16)

Graphics Processor
Adapter : NVIDIA GeForce 8500 GT (16SP 1.4GHz, 255.7MB 2x400MHz)

Storage Devices
WDC WD1600AAJS-08PSA0 (160GB, SATA300, 3.5", 7200rpm, NCQ, 8MB Cache) : 149GB (C:)
ST3200826AS (200GB, SATA150, 3.5", NCQ, 8MB Cache) : 186GB (E:)
ST3200826AS (200GB, SATA150, 3.5", NCQ, 8MB Cache) : 186GB (F:)
FUJITSU MHY2250BH (250GB, USB/SATA150, 2.5", 5400rpm, NCQ, 8MB Cache) : 233GB (G:)
HL-DT-ST DVDRAM GSA-H62N (SATA150, DVD+-RW, CD-RW, 2MB Cache) : 467MB (D:)

Logical Storage Devices
Hard Disk (C:) : 149GB (NTFS) @ WDC WD1600AAJS-08PSA0 (160GB, SATA300, 3.5", 7200rpm, NCQ, 8MB Cache)
Video (E:) : 186GB (NTFS) @ ST3200826AS (200GB, SATA150, 3.5", NCQ, 8MB Cache)
Audio (F:) : 186GB (NTFS) @ ST3200826AS (200GB, SATA150, 3.5", NCQ, 8MB Cache)
RCT3 (D:) : 467MB (CDFS) @ HL-DT-ST DVDRAM GSA-H62N (SATA150, DVD+-RW, CD-RW, 2MB Cache)
Jonno250gb (G:) : 233GB (NTFS) @ FUJITSU MHY2250BH (250GB, USB/SATA150, 2.5", 5400rpm, NCQ, 8MB Cache)

Peripherals
LPC Hub Controller 1 : Giga-Byte (ICH9) LPC Interface Controller
LPC Legacy Controller 1 : ITE IT8718F
Audio Device : Giga-Byte (ICH9) HD Audio Controller
Serial Port(s) : 1
Parallel Port(s) : 1
Disk Controller : Giga-Byte (ICH9) 2 port Serial ATA Storage Controller 1
Disk Controller : Giga-Byte (ICH9) 2 port Serial ATA Storage Controller 2
Disk Controller : Giga-Byte JMB36X PCIE-to-SATAII/IDE RAID Controller
USB Controller 1 : Giga-Byte (ICH9) USB Universal Host Controller
USB Controller 2 : Giga-Byte (ICH9) USB Universal Host Controller
USB Controller 3 : Giga-Byte (ICH9) USB Universal Host Controller
USB Controller 4 : Giga-Byte (ICH9) USB2 Enhanced Host Controller
USB Controller 5 : Giga-Byte (ICH9) USB Universal Host Controller
USB Controller 6 : Giga-Byte (ICH9) USB Universal Host Controller
USB Controller 7 : Giga-Byte (ICH9) USB Universal Host Controller
USB Controller 8 : Giga-Byte (ICH9) USB2 Enhanced Host Controller
FireWire/1394 Controller 1 : Avlab Technology TSB43AB23 1394a-2000 OHCI PHY/link-layer Controller
SMBus/i2c Controller 1 : Intel 801xx/63xx SMBus

Printers and Faxes
Printer : Kyocera Mita FS-1010 KX (600x600, USB, Colour)

Network Services
Network Adapter : Realtek RTL8168/8111 PCI-E Gigabit Ethernet NIC - Packet Scheduler Miniport

Power Management
Mains (AC) Line Status : On-Line

Operating System
Windows System : Microsoft Windows XP Professional 5.01.2600 (Service Pack 2)
Platform Compliance : x86