Well it turned out to be a BIOS problem after all , however clearing CMOS didn't seem to reset the setting , or is it there by factory default? (Most likely!)
The problem was in BIOS , option NVIDIA Core Calibration was enabled , which was trying to unlock that athlon to 4 cores.. I have NO idea how it booted sometimes with that option enabled , but i'm glad I could enter BIOS. I entered bios by removing and playing with RAM slots then it finally started...
Thanks for trying to help... reps
| CPU | Motherboard | Graphics | RAM |
|---|
| AMD Phenom II X3 720 Black Edition (3,3GHz @ 1.25) | Gigabyte GA-MA790XT-UD4P | ATI Sapphire HD 5830 Game Edition (1GB GDDR5) | 4 GB Corsair XMS3 1600MHz (9-9-9-24) |
| Hard Drive | Optical Drive | OS | Monitor |
|---|
| OCZ Agility 3 SSD 240 GB | _NEC DVD_RW ND-3500A | Microsoft Windows XP Professional SP3 | Samsung 20" LCD |
| Keyboard | Power | Mouse |
|---|
| Trust keyboard | Corsair TX 650 | Microsoft USB Wheel Mouse Optical |
| View all |
hide details
| CPU | Motherboard | Graphics | RAM |
|---|
| AMD Phenom II X3 720 Black Edition (3,3GHz @ 1.25) | Gigabyte GA-MA790XT-UD4P | ATI Sapphire HD 5830 Game Edition (1GB GDDR5) | 4 GB Corsair XMS3 1600MHz (9-9-9-24) |
| Hard Drive | Optical Drive | OS | Monitor |
|---|
| OCZ Agility 3 SSD 240 GB | _NEC DVD_RW ND-3500A | Microsoft Windows XP Professional SP3 | Samsung 20" LCD |
| Keyboard | Power | Mouse |
|---|
| Trust keyboard | Corsair TX 650 | Microsoft USB Wheel Mouse Optical |
| View all |
hide details