The 32-bit version is the one you require. The x86 actually comes from the model number of the earlier Intel family of processors themselves, namely the 286, 386, 486, 586 (pentium). These were all 32-bit processors, so the term x86 means the same as 32-bit, and is, in some cases, interchangeable.
Finally, Success! SP1 has installed!
It only took another Format, and now allowing Vista to install any drivers what so ever. straight through all the updates and SP1 went in first time.
So, it would seem the trick is to do like you say... clean install... get SP1 straight away.
Should I be checking for drivers which may now be out of date? ANy ideas from you experience what I should do?