It could be a number of things.
How much free, freshly defragmented space is on your C drive? Are you using more than one drive to edit your video? If so, is your second drive formatted NTFS rather than FAT32?
You say you're using AVIs as your source video. Are these DV-AVIs captured over FireWire from a miniDV camcorder?
Also, did you ensure, when you started up this video project, that you saved it within its own, new folder rather than saving its .prel project file to an open area of your hard drive?
Finally, if you're using version 4, I'm assuming you're also using an older operating system and an older computer. If so, your system could well benefit from some basic operating system maintenance.
A BSOD is a major problem, and is very often a sign of hardware issues. The main causes are:
Heat buildup - in the CPU, or the HDD's
RAM - bad, or going bad
PSU - going bad, or improperly connected
MoBo - going bad
This ARTICLE will link to tools that will help you track those elements, and possibly show the bad element, or potentially bad element.
I would also change Reboot on Error, to OFF, so that you can write down the report on the BSOD. There might be something in that load of "abstract code" that will be helpful, but maybe not. Also, when one reboots after a BSOD, Windows will usually yield an error message to the effect of "Windows has recovered from a serious problem... " and will often help you trace the issue. Also, this ARTICLE will give you tips for finding clues as to what was happening, just before the BSOD.
If nothing else works, see this ARTICLE.
Before doing anything else, I would solve the BSOD issue.