My Built Need Help Please

Now, £380 is a little bit low of a budget to build a Core 2 Duo rig from the bottom up. The parts you picked, however, do have issues. You selected an LGA775 board that is a hybrid board that supports DDR and DDR2, and both AGP and PCI-E video cards. Although that's nice, all that compatibility does cause stability issues. Since this is a new build, I'd get a good board that supports DDR2 and PCI-E (the current standards).

Here is an example of a basic Core 2 Duo rig, although it's quite a bit more than you probably had in mind in terms of costs:

CPU: Intel Core 2 Duo E6300, Socket 775, 1.86 GHz £117.32
MoBo: Gigabyte GA 965P-S3 iP965, S775, PCI-E (x16) £78.48
RAM: 1GB (2x512MB) CorsairTwinX XMS2 DDR2 PC2-6400(800) £107.68
Video: 256Mb XFX 7900GT Standard, PCI-E (x16) £134.88
HDD: 160 Gb Western Digital WD1600YS 7200 rpm, 16MB Cache £43.25
DVD: LiteOn LH-18A1H 18X DVD+/-RW/RAM Lightscribe black £22.50
PSU: 450w FSP ATX-450PNF PSU ATX2.1 ATX12V PCI-E/SATA £47.78
Case: Scan Colors IT 6001-C34 MicroATX Case Black/Silver £29.32

Net Total £494.64
Carriage £12.73
V.A.T. £88.79
TOTAL £596.16

To stay closer to your budget, I'd recommend to go for an AMD rig with a single core AM2 processor. Performance won't be as good as the Core 2 Duo rig, but it's easy to upgrade in the future

CPU: AMD AM2 Athlon 64 3200 Orleans Core, 2.0GHz, 512KB Cache £52.75
MoBo: Gigabyte GA M55S-S3, NF550, S AM2, PCI-E (x16) £52.86
RAM: 1Gb (2X512Mb) Corsair Value Select, DDR2 PC5300 (667) £74.65
Video: 256MB XFX 7900GS PCI-E (x16) £109.63
HDD: 160 Gb Western Digital WD1600YS Caviar RE 7200 rpm, 16MB £43.25
DVD: LiteOn LH-18A1H 18X DVD+/-RW/RAM Lightscribe black £22.50
PSU: 450w FSP ATX-450PNF PSU ATX2.1 ATX12V PCI-E/SATA £47.78
Case: Scan Colors IT 6001-C34 MicroATX Case Black/Silver £29.32

Net Total £368.28
Carriage £12.13
V.A.T. £66.57
TOTAL £446.98

Now, personally I'd save up the extra £150 for the Core 2 Duo rig, since the performance will be a whole lot better!