Falci: I did a little bit of checking in OCZ's site and came to the conclusion that I won't get a new RAM stick from them.
No distress though. I found a decent offer on a pair of Kingston 2GB DDR2 800MHz sticks and bought them.
The only problem is that I'll probably receive them through mail late next week. But at least my machine is still functioning until there.
Kingston and Corsair make better modules than OCZ anyway. G.Skill is good for overclockers, but really only worth the investment if you
truly want to overclock. If you want to run at stock speeds, then get stock modules.
In a similar issue to yours, I just ordered a second 2x2GB kit from Corsair for my own PC. It's the exact same model, the exact same speed and timings, and the exact same voltage. Only the version numbers are different (the older kit is version 2.2, and the newer is 8.2. The difference between versions, as the tech explained it to me, is a difference between materials used and outsourced manufacturers). Apparently, it was so much of a difference that it caused a critical hardware failure in the new kit, and I had to RMA it from the merchant I bought it from. After explaining the situation to Corsair's tech support, I was advised to disable "Unganged mode", and to dial back the speeds of all modules from 1333 to 1066 (666MHz to 533Mhz, approximately) . In addition, I was told that it may be prudent to, since my mainboard (MSI 790FX-GD70) was tailor-made for overclocking, increase the voltage from the stock 1.50V to 1.65V. After effecting these changes, I ran MemTest86+ (which I recommend you do as soon as you install your replacement modules) off a USB stick for about three complete passes. Everything seems to look "so far so good".
Bear in mind, the advice given to me was based on my system specifications. I strongly advise that you get professional technical help from Kingston about installing a mix-matched kit. Make sure you have all the latest drivers for your peripheral hardware, and the latest BIOS for your mainboard, and a list of model numbers for all of these for the tech, should you decide to talk to one.