Hello Everyone, In attempting to fix my son's PC (he was getting blue screens, corrupted registry and files, weird colored verticle lines on monitor at startup, p2p program crashing), I decided after using motherboard monitor that cpu temps from 54C idle to 63C load might be a bit high, I thought I'd replace the 4 year old Arctic Silver with the latest Arctic Silver 5, When I first wiped the old paste off the core, I got a small bit of it on the ceramic portion of the cpu, and having read that it could be slightly conductive, I used Goof Off and 91% alcohol (recommended on their website) to clean the core and the ceramic area around it. It looks fine. I applied the new paste, reassembled, switched on the power and I get the green light on the MB, the CD lighting up, no start up test beeps, nothing on the monitor, no access to bios. I've reset the CMOS, disconnected every peripheral, hard drives, etc. I had another duplicate MB by chance, I configured it and installed it and gained the hard drives powering up but everything I stated above remained the same. I feel the power supply is working fine. Did I short the CPU? Is there a definitive test to know that a CPU is fubared? A new Athlon XP 2400 is only about $70 but I'd like to know this one is truly shot before I spend more on a system that is, for all intents and purposes, somewhat ancient. Any help greatly appreciated. Thanks Tom __________________ Lian-Li PC 60 Enermax EG 465P-VE(FC) AMD AthlonXP Palamino Model 1900(1.6 ghz) Asus A7V266 E 3X256mg CORSAIR PC2400 DDR Swiftech MCX 462 Heatsink Sanyo Denki Fan Swiftech Rheostat Arctic Silver II 2XIBM 60GB 7200rpm Deskstar GXP Raid 0 Plextor 24X10X40 CD-RW IDE Pioneer DVD-116 Atapi16X/40X V8200 T5 Pure Geforce3 Ti500 Nvidia Titanium Creative Audigy Platinum 250MB Zip Drive 3COM 3C905CXTM PCI 10/100 Teac FD235HF(704) 1.44MB Sony CPD-G420S Monitor MS Windows XP Pro Edition

That you put the CPU in another known good motherboard and it didn't boot is a fairly definitive test. Maybe you static zapped it when you were cleaning it, or maybe you didn't get the heatsink quite right the first time. But it sounds dead. It's nice to have an old 750 Duron or something similar around to help diagnose these things.

The original problems sound like something other than overheating to me though. When I've had heat issues, the number one problem would be hard lock ups, requiring me to hit the reset button to reboot. Unless you have a severe heat issue (like a dead fan on the heatsink) you won't have heat problems on boot up; it needs to run a little while first. Those problems sound more like bad memory or a dying video card to me.

I agree that the original problem probably was not an overheating issue. When you reapplied the AS5, did you only use a small dab about the size of a grain of rice & spread it thinly & evenly over the CPU core? One common mistake is installing the heatsink backwards. The heatsink has a "notch" on one end which is meant to fit over the "step" in the CPU socket. Install it backwards & it doesn't make full contact with the core & the CPU can fry in a matter of seconds. Asus A7N8X-X 1800+ @ 8.5 x 200MHz 768MB PC3200 2.5-3-3-7 Asus A9550GE/TD 128MB WinME/WinXP Pro