Hardware issue, troubleshooting help

I've been having interesting issues with my desktop lately (see sig), and wanted some advise about my options...

It started with my nvidia onboard LAN, it decided to die (continuely disconnecting/reconnecing). Driver updates unfortunately did not fix the issue, so I've had to rely on the marvel yukon onboard LAN (which has the same issues, random disconnects/reconnects, but not as frequent). Shortly after this occurred, my PSU died. Having got a replacement, all other components seemed ok, apart from the LAN. To add to that, my system seems to have a problem cold-booting. I'll get a BSOD (usually "IRQ less than or equal to") the first couple of attempts, after which it'll boot up fine like nothing ever happened. On some occasions, after booting, my antivirus (previously symantec corporate, now kaspersky) will state that my definition files have become corrupt, but once updated are fixed. Otherwise I don't notice any particular instability in my usual computing activity.

I thought a reformat w/XP SP2 might do the trick, but unfortunately it didn't and I'm having the same issues...My system is not overclocked. I've checked my new PSU's rails and they seem fine under all conditions. If anyone has some suggestions, I'd love to get this issue under wraps! Thanks in advance, cheers

Have you tried running memtest86 to see if the memory errors?

Yeah, BSODs typically indicate dying memory, so you'll definitely want to run memtest86+.

Did you recently hook up something new, or install some new software or drivers? Took me months to realize that a printer driver was causing me a world of hurt, because I had added other new stuff at close to the same time.

I recall from my o/c days that BSODs usually pointed towards RAM. From when I first setup this rig, I used to get a lot of instability. I found that when I changed RAM slots (formally slots 1 and 3, now 1 and 2), it solved the issue, and my pc was for all accounts rock-solid for over 1yr, up until the onboard LAN and finally PSU died recently.

Once I'd installed the new PSU, I did notice my computer seemed a bit more laggy. Upon looking in the BIOS, I found that the ram was set to 133 Mhz (the m/b was using "BY SPD" setting) and voltage 2.5v. This ram is rated to 250mhz @ 2.8v, so I bumped the voltage up to 2.8v and its speed up to run 1:1 with my processor @ 200mhz. Upon closer inspection of my BIOS, I found it strange that the genie bios reports the ram voltage as "DRAM 2.5V voltage", so I'm wondering if in fact I changed the right setting (manually adjusted using "DRAM control voltage" setting)? I'm a bit lost on this DFI board...I'll run some memtest overnight, and hopefully have some results. Otherwise, any other suggestions appreciated cheers.

It was brought to my attention that perhaps the problems I'm having may concern my ram, in particular the brand I'm using has not had a good reputation of late for reliability. I was doing a thread search, and not too many results on bad kits, just those that I read on newegg's link. Although consensus seems that they don't behave with too high VDIMM, which seems weird considering they're rated to 2.8v. I might turn it down a notch to 2.7v since I'm not running @ DDR500, otherwise any other suggestions? I've been getting a lot of CRC errors when extracting archives lately, I guess that's not a good sign either...thought that was solely dependant on hdd though, and since I'd reformatted I installed nvidia's IDE drivers without thinking (never used them before, read about similar crc issues). Cheers

*UPDATE* Loosened my timings to stock (3-4-4-10), ran memtest during the day today (10+ hrs, standard tests), just came home and found one error =$ on the 9th pass during test #4. I recall when I had some bad ram in the past, it showed more than one error in memtest whereas this present case it had performed a further 2 passes after the first instance and not encountered any errors *shrug* where to from here? Cheers