Upgraded old custom-built system to new Athlon X4 630 and Biostar Mobo AMD3, with new DDR2 1066 ram (4MB). Kept PATA WD 160 HD with existing Win7 32 bit boot. Old power supply is 20-pin, for new 24-pin connector, but GPU is on-board (not PCI) for now. Starts fine, POSTs OK, but Win7 starts and then stops 5 secs in, w an unspecified error. System Repair option finds all sub-systems OK, but sometimes says some part of BIOS config is wrong. From command prompt and in BIOS HDD is present. Had to manually set the RAM 1066 timing. Don't see anything else mis-configured. What next to check?