BIOS virus

By eku1 ·
My father reported strange behaviour on his PC. First the mouse would stop responding after the PC being on for a while. I took a look at it and since he had a firewall and a reputable antivirus software which didn't find anything, I monitored the problem. Few days later the PC would stop randomly which eventually led to only the BIOS coming up and now nothing. I moved his HDD to my desktop to try to move some data over. Needless to say, 2 weeks later my desktop started doing the same thing. I went into the BIOS and noticed that the CPU temp was super high 190F+. It takes about 30 seconds for it to hit 199F and then the PC shuts off. I checked the fans and everything is fine. My suspicion is that something wrote to the BIOS and adjusted the CPU temp value. I started the PC after it stopped and I pressed CTRL+ALT+DEL because I missed the BIOS setup prompt. Now the PC comes on, no video, and only sound that says "overclocking failed". Before I got locked out, I checked the overclocking and it was turned to standard (off). The board is ASUS PC800E-Delux and the boot sector virus protection in BIOS was not turned on. I removed the battery for 5+ minutes and no difference.

Another observed detail is that the MB temp starts at around 20C and the CPU starts at 70C to 75C. At about 93C it auto shuts down.

All help is greatly appreciated.

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BIOS Virus

by TheChas In reply to BIOS virus

If it is a BIOS virus, they can be difficult to eradicate.

The most effective way is to replace the Flash ROM that holds the BIOS.

At the same time, you need to clear the CMOS memory AND remove the virus from the hard drive.

As you need to boot the system in order to flash the BIOS, the virus can reinfect while the BIOS ROM is being flashed.

Now, you need to decide if the $25 or so for a new BIOS ROM is a worthwhile investment or if you want a new motherboard or system.


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by eku1 In reply to BIOS Virus

Problem solved. It seemed like too much of a coincidence for 2 PCs to have the same problem and for it to not be a virus. I took the CPU fan off anyway to make sure that things were fine. The PC hasn't been moved in years so I figured there was a small chance of something coming loose, but anyway. Well, as soon as I touched the CPU fan, one of the plastic loops that hold the CPU fan on the motherboard fell off. I guess the CPU fan was loose (not visibly) and therefore wasn't cooling. I replaced the motherboard attachment and the fan and it is fixed. Thanks for your help. Still no idea what caused the problem on my dad's PC as the fan I'm now using is from his PC.

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