All downloads corrupt via Onboard LAN ?

[zahid]

Built a new rig.

PENTIUM D 945 3.4 GHZ
400W 72% EFFICIENT PSU
MAXTOR 250GB SATA
LITE-ON 20X DVDRW
MSI PT890 NEO-V Motherboard
NVIDIA 8400GS
Vista Ultimate retail

Thing is if I download and RUN anything from the net via the Onboard LAN, I always get UNKNOWN PUBLISHER and can't install nothing.
If I SAVE and try to install, I always get Files are Corrupt error.
I have tried with WINZP, WINRAR and NVIDIA DRIVERS download - all same problem!

Apart from this, The Performance assessment tool always crashes. It seems to be an NVIDIA problem ( from Googling ), but I can't find no solution.

Any help would be seriously appreciated. I am tearing ym hair off over this!

 

[zahid]

All parts are NEW. I have run memtest too. no probs.

RAM is 2X1GB KINGSTON ELPIDA

 

[zahid]

BUMP! ANYONE????