I'm having trouble with my newly built PC whenever I try to turn it on.  The machine turns on fine, but only on the second power up.  I'll try and turn it on, the machine won't post, hold the power button for 4 seconds, it turns off, then turn it back on and it works fine.  I don't have any idea what the problem is.  
 
My other problem is that whenever I try and go into sleep mode, the PC won't awake from it.  It will jus tstay idle and the only way to recover is to once again shut the system down.
 
I also get the "CPU not recognized.  Please upgrade the BIOS to unleash it's full potential" message on startup so maybe that has something to do with it.  The components I have are:
 
-ASUS P5N-E SLI LGA 775 NVIDIA nForce 650i SLI ATX Intel
 
-Intel Core 2 Quad Q9300 Yorkfield 2.5GHz LGA 775 95W
 
-EVGA 512-P3-N871-AR GeForce 9800 GTX(G92) 512MB 256-bit GDDR3 PCI Express 2.0 x16
 
-OCZ SLI-Ready Edition 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Memory
 
-Seagate Barracuda 7200.10 ST3250410AS 250GB 7200 RPM SATA 3.0Gb/s Hard Drive
 
-SIGMA SHARK SP-635 635W ATX12V V2.01 Power Supply
 
-Windows Vista Ultimate 64-bit
 
Any help would be greatly appreciated.  Thaks guys!

Are you using the 0901 bios (2/20/08 per Asus' website)?  Also, do you have the latest nVidia nForce chipset drivers for that board (v15.08 per nVidia's website)?
 
If not, I'd try those and see if it offers any relief.

You definitely need to upgrade bios to get rid of the cpu not recognized.