is it safe to use CCleaner in XP x64? cos it edit the registry etc? and there shld be differences between 32 bit and 64 bit right...

i got an error on my first run...

Did you read this first?

I run it without hesitation on my XP 64 rig and it works awesome.

AFAIK, been awhile to test it, but it does report .net 1.1 registry keys.
Dot net 1.1 works with xp x64 bit (including the sp1+hotfix too!), it's just not A-OK by microsoft per se, but it works.
CCleaner at least used to report them keys, but they can be safely removed, as most will not need .net 1.1 on xp x64bit at all.
Also it is getting old and .net is at version 3.5 and most if not all have moved onto .net 2.0 at least.
I only miss that CCleaner does not read all Run and Runonce registry keys, so i can use it to remove all bloat from startup.
But good program.