BSoDs (Windows restarts itself)

[Crécy]

Originally Posted by Arclight

Iirc he just rebuild the thing after a faulty PSU.

Yes, the PSU was changed to a better one.

Originally Posted by Feuer Frei!

If this is a new computer, you may simply have some bad memory. Try taking out a stick for a few days (if you have two) and if it still crashes, put the other stick back in and take out the first.

Have you downloaded and installed all the manufacturers drivers, or just used the built-in Windows ones?

Heat can be another issue, as well, as flaky power supplies.

When you installed 7, did you install it onto a newly created partition?
A common side effect of faulty memory is data corruption, so what I usually recommend in severe cases where there are a lot of memory errors, or memory is likely to have been faulty for some time is a clean install to clear any corruption.
Run MemTest:
http://www.memtest.org/

Let us know how you go.

Yes, I have a fairly new computer (one-year-old). I installed chipset updates. I deleted both partitions and then created a 100gb partition for windows 7. I installed it there.

Ran CHKDSK as Arc suggested and at least it didn't find any bad sectors. I will try memtest now.

Which memtest file I should download?

Thank you both for your help so far!