Vista home 32 sp2 bsod 21a

smos585

Your vote please!

I recently had to use malwarebytes to remove the Vista Defender virus.

Each day the system fails on start-up with bsod 21a; repair option just shuts down. Usually within a restart or two it will start normally and work all day without issues, even if restarted. Yesterday I also got a 7f and 4f before it would start.

I have run chkdsk and memtest all are fine. I have also run sfc which did repair some files and the only file it said it couldn't fix was a help file. It has a x1550 graphics card where I notice that one of the "gold" contacts is shorter than the others.

Normally a 21a would indicate a software/driver issue. But the problem and how it shows indicates that it may be hardware, ie a weak connection which when warmed up works fine.

Repair install or re-install of Vista is a b*gg*r, especially if we then find out it is hardware. As the problem is so intermittant, our options to try things takes days.

So before we decide what to do just thought I'd see what others thought.

NiftyDigits

Same problem when booting from a Live CD?

closed

backup and factory restore

Toxteth_OGrady

Given that it is an old os and therefore probably an old cpu without thermal management, along with the variety of bsod errors and shutdowns during repair I would guess it's an overheating cpu.

Clean out case/fans and, if necessary, apply fresh TIM to cpu.

smos585

NiftyDigits wrote: »

Same problem when booting from a Live CD?

Not yet (each test has to wait 24 hours!!!), thanks.

Closed wrote:

backup and factory restore

Thanks for yr opinion.

Toxteth_OGrady wrote:

Given that it is an old os and therefore probably an old cpu without thermal management, along with the variety of bsod errors and shutdowns during repair I would guess it's an overheating cpu.

Probably the opposite to overheating as it only happens when very cold, I thought about reseating the cpu too. Thanks for your opinion.

Toxteth_OGrady

smos585 wrote: »

Probably the opposite to overheating as it only happens when very cold, I thought about reseating the cpu too. Thanks for your opinion.

Bearing in mind that a cpu heats up extremely quickly from a cold boot and can be running at 100% load for many minutes whilst all the start up services and apps load/run.

You can easily check for overheating by installing something like RealTemp to monitor cpu temp from your Windows desktop. You can use this in conjunction with a stress test program such as Prime95 which will keep your cpu max'ed out at 100%.

waddler_8

smos585 wrote: »

I recently had to use malwarebytes to remove the Vista Defender virus.

Did it do the same prior to the infection. The problem could just be coincidental, but are you sure it isn't still infected? It's not unknown for malware such as this to also come along with a rootkit.

robmar0se

Toxteth_OGrady wrote: »

Bearing in mind that a cpu heats up extremely quickly from a cold boot and can be running at 100% load for many minutes whilst all the start up services and apps load/run.

When things heat up they expand, hence if there was a poor connection the quick heating up would explain why it doesn't re-occur during the day. So it not likely to be overheating as such?

If the connectors on the x1550 are imperfect as the OP suggests, try running removing it and run with another card.

Toxteth_OGrady

robmar0se wrote: »

When things heat up they expand, hence if there was a poor connection the quick heating up would explain why it doesn't re-occur during the day.

Apart from the elementary physics lesson ( ) I'm not sure I follow what you are saying??

Overheating is just one aspect to rule out. When it comes to random instability/bsods I always like to rule out hardware; primarily memory/heat/power.

It's possible, albeit unlikely, that the OP uses it in such a way that the only time the cpu is 100% loaded is during startup.

robmar0se

Toxteth_OGrady wrote: »

Apart from the elementary physics lesson ( ) I'm not sure I follow what you are saying??

Overheating is just one aspect to rule out. When it comes to random instability/bsods I always like to rule out hardware; primarily memory/heat/power.

It's possible, albeit unlikely, that the OP uses it in such a way that the only time the cpu is 100% loaded is during startup.

I agree.....I think yr suggestion about the PSU is a good one, probably worth swapping out both the PSU and the graphics.

smos585

Toxteth_OGrady wrote: »

Overheating is just one aspect to rule out. When it comes to random instability/bsods I always like to rule out hardware; primarily memory/heat/power.

It's possible, albeit unlikely, that the OP uses it in such a way that the only time the cpu is 100% loaded is during startup.

robmar0se wrote:

I agree.....I think yr suggestion about the PSU is a good one, probably worth swapping out both the PSU and the graphics.

Thank you for your suggestions both.

I did switch out the Graphics, then the psu, but still got the same 21a error. put the old items back and booted fine (warmed up I guess).

waddler_08 wrote:

Did it do the same prior to the infection. The problem could just be coincidental, but are you sure it isn't still infected? It's not unknown for malware such as this to also come along with a rootkit.

Usually the system is on standby rather than switched off at the mains, so can't say whether it was
there before. I did remove the virus exactly as beepingcomputer said - there is/was no indication that it might have infected any system files (have run sfc). If this is as a result of the virus, must be very clever only to happen when system is cold!!:)