[HELP NEEDED] Errors on all OSs / Bad NAND blocks?

For the last several months I noticed that my Androind builds are hunging up, sometimes several times a day, sometimes once a month. While using it might just stuck/freeze and it doesn't react at all until I remove the battery and instert it back.

Recently I decided to browse the forums and read about possible bad sectors on my NAND memory. Somebody mentioned that I should use MTTY and do >task 2a, which actually confirmed that I have a bad block, bud it's only one. The issue is that now being tired of MIUI ICS which hungs quite often, and ICS CM9 builds which are quite stable but at some point are freezing as well, I decided to move to WP7, which earlier was running perfectly on my phone and was able to install those ROMs without any problems. Today I found out that while flashing WP7 ROMs I can't get over Flashing Partition 7, same error with 3 different builds..

Also today I flashed an original WM 6.5 build, which was installed correctly but after 5 minut had an unexpected reboot...

I trying everything I know, Task 29, reinstall HSPL, reinstall MAGLDR, different partitions for CWR, looks like nothing helps..

Does anybody has any ideas or hints?

What I noticed that under normal usage (basic applications, internet browsing, email and listening to music) nothing bad happens, at least on ICS CM9 with HWA.. It freezes when it gets warm. Under heavy usage it might get stuck and while it's still hot I can't really load the system properly, as it will freeze instantly. Once it settles down, in about 15minutes, the system would work like nothing happened. I actually discovered yesterday that I still have 2 months of warranty left, maybe I should just return to the shop. But that means I need to flash back WM 6.5

Well, in the end I had to return my phone to the shop today, as it's still under warranty.
I'm curious if there are going to do something with it, fix it, replace, or just return back, as I'm not really sure if they will find any errors, but I hope they will.
Just in case, I flashed the original WM RUU from HTC, and yesterday, while playing with it for a while, it rebooted a couple of times, and was quite hot as well.

Last week-end I've been to Lisbon, were we had 32 degrees at some points, so my phone was freezing every 5 minutes, when I put it in front of the blowing AC fan from the car it could work like that for hours without any issues, but I suppose it should work like that always and in all conditions. This made me understand that the overheating due to a faulty board could be the root cause of all problems. I suppose that even the bad blocks appeared after the overheating issue appeared

I will write here an update when I'll get my phone back from the service.