Randomly occurring BSOD

Hi All, my friend has a laptop that has been getting BSOD rather frequently (a few every day). The laptop is a Sony VAIO (US-SVS131190X-LBOM) run Win 7 Home Premium with 4 GB RAM fixed onboard. I've asked him to run memtest, and it has come back clean (I'm really hoping this isn't a memory issue, especially if the RAM is soldered on). I've checked for driver updates, and that hasn't led me anywhere. Any suggestions on what to try next? Any and all help is appreciated!
Here's what WhoCrashed gave:

This was probably caused by the following module: ntoskrnl.exe (nt+0x74EC0)
Bugcheck code: 0xA (0x80, 0x2, 0x1, 0xFFFFF8000307FDFF)
Error: IRQL_NOT_LESS_OR_EQUAL
file path: C:\Windows\system32\ntoskrnl.exe
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: NT Kernel & System
Bug check description: This indicates that Microsoft Windows or a kernel-mode driver accessed paged memory at DISPATCH_LEVEL or above.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
The crash took place in the Windows kernel. Possibly this problem is caused by another driver that cannot be identified at this time.