Two stop errors within 1.5 hours

[Agravice]

I've had stop errors on and off for a few months now and I've never really known the cause of them. I've ran scandisk /f /r several times and also done that RAM check which has come back clean every time. This morning my comp restarted without warning, I ran defrag once it came back up and let it run through the night. Well apparently it restarted again only 1.5 hours later. Here are both minidumps, I run Windows XP SP2.

 

[cpc2004]

Two minidumps are not insufficient to find out the root cause of the problem. Zip 5 to 6 minidumps and attach the zip files here (note the maximum limit of each attachment is 100k).

Preliminary fining
The crash is random. Probably it is related to faulty ram or software error of Norton AV.

Debug report Summary
Mini012207-01.dmp BugCheck 1000000A, {84ac, 2, 1, 806ff904}
Owning Process 85c03da0 Image: WoW.exe
Probably caused by : portcls.sys ( portcls!CIrpStream::GetPosition+7e )

Mini012207-02.dmp BugCheck 1000000A, {80000, 2, 1, 806ffa2a}
Owning Process 873c47f8 Image: System
Probably caused by : SYMEVENT.SYS ( SYMEVENT+76a2 )

 

[Agravice]

Sorry about that, here are my latest 6 minidumps zipped together.

 

[Tedster]

you might have some driver issues.

 

[Agravice]

/bump

Some driver issues eh? I'm not a real computer whiz here not sure how to figure out which ones are having problems. If anyone can show me which ones need updating it'd be much appreciated.

 

[cpc2004]

One of the minidump is crashed at IRQL 28 (ie timer IRQL) and it is symptom of hardware error. Probably it is ram problem. Downclock the ram may resolve the blue screen problem. Refer this problem. If it still crashes, run memtest to stress test the ram.

Debug report your minidump
Mini112606-01.dmp BugCheck 1000000A, {54, 1c, 1, 804e1630} <-- Crash at Timer IRQL 28
Probably caused by : ntkrnlmp.exe ( nt!KiUnlinkThread+0 )