Installed new processor and computer doesnt turn on just flashes green steadily?

CPU • Supports 64-bit AMD® Athlon™ 64 processor (Socket 754) • Supports 2800+, 3000+, 3200+, 3400+, 3700+ • Supports Sempron 2600+, 2800+, 3000+, 3100+, 3300+ Chipset • VIA® K8M800-CE Chipset - HyperTransport connection to AMD Next Generation of CPU - 8 or 16 bit control/ address. data transfer both directions - 800/600/400/200MHz "Double Data Rate" operation both direction - AGP v3.0 compliant with 8X transfer mode - On-board Graphic shared up to 64MB • VIA® VT8237R Chipset - Ultra DMA 66/100/133 master mode EIDE controller - Integrated dual channel native Serial ATA/RAID controller that will supply 150MB/s and support RAID 0, RAID 1 - ACPI & PC2001 compliant enhanced power management - Supports 8 USB2.0 ports. (Rear x4/ Front x4) Main Memory • Supports two 184-pin DDR SDRAMs up to 2GB memory size • Supports DDR400*/DDR333/DDR266 DDR SDRAM (*Refer to MSI recommended modules) • Note: PC3200 (DDR400) maximum 4 banks (2 double-sided) only

I can't seem to find any usefull information as to why there may be a LED flashing on the motherboard. Re-check the memory speed, and configuration, as well as the CPU that it is supported. This seems to be a fairly new motherboard, it may still be under warranty, contact MSI and request an RMA if you feel the motherboard is faulty.

Check your new processor if supported by motherboard.